bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of rose bengal and sulfhydryl reagents on stromal fragments of rabbit and human erythrocytes
Authors: Dastoli Frank R. , Green James W.
Published: February 2005

Stromal fragments of human and rabbit erythrocytes, prepared by osmotic hemolysis, were used as sources of ATPase in a study of the action of the fluorescein dye, rose bengal, and of sulfhydryl reagents on this membrane component. Only the Na‐K independent ATPase was systematically studied but the dye was observed, at concentrations of 10−3 M, to completely inhibit the Na‐K dependent activity. Over a concentration range of 1.6 × 10−7 to 10−3 M the dye had a graded inhibitory effect on the Na‐K independent ATPase in Tris buffer with little difference in the sensitivity of the enzyme from the stroma of the two species. The activity of the cation independent enzyme was not changed by darkness or anaerobic conditions in the presence of the dye and its action could not be attributed to photosensitization. Repeated washing to remove the dye failed to reduce its effect on rabbit stroma and only partially succeeded with human stromal fragments. The dye was shown not to be a competitive inhibitor of ATP for the stromal ATPase of either species. Attempts to reduce the rose bengal effect by use of the sulfhydryl agents, glutathione or cysteine were unsuccessful although glutathione did protect ATPase against the common sulfhydryl inhibitors. It is concluded that the dye is affecting an essential group on or near the enzyme either by direct bonding or irreversibly changing essential bonds.
The effects of hibernation on the in vitro synthesis of DNA by hamster lymphoid tissue
Authors: Manasek F. J. , Adelstein S. J. , Lyman C. P.
Published: February 2005

DNA synthesis was studied in vitro in lymphoid tissue taken from hibernating, cold adapted and active golden hamsters in an attempt to elucidate the mechanism of suppressed DNA synthesis during hibernation. The rates of DNA synthesis at temperatures varying from 4 to 37°C were greatest in cells from active animals, less from cold adapted and least from hibernating animals. The depression in cells from cold adapted animals was 70% reversible by returning the animals to a warm environment 40 minutes before they were sacrificed but the hibernating animals had to be aroused for more than 12 hours before their rates recovered, suggesting a different mechanism responsible for depression in these two instances.

Radioautographic and biochemical measurements of DNA synthesis in cells taken from hibernating animals indicated that the depressed synthesis seen during hibernation is the result of a reduction in the percentage of cells engaged in DNA synthesis. This implies that the low body temperatures of hibernation produce a block in the cell cycle of lymphoid cells not unlike that observed when other mammalian cells are exposed to cold in vitro.
Circus reexcitation as a cause of repetitive activity in crayfish lateral giant axons
Authors: Kusano Kiyoshi , Grundfest Harry
Published: February 2005

Unpolarized electrotonic connections between the two lateral giant axons of crayfish nerve cord have been demonstrated. Presumably they are also the sites of the tightly coupled unpolarized ephaptic junctions by which activity from one axon may be transmitted to the other. Commissures between the segmental branches of the two axons are probably the sites of the junctions. If septal transmission is blocked in one axon, the inactive segment can be excited by the activity of the other axon. The segmentally arrayed ladder of ephaptic junctions forms a series of delay lines and circus activity can occur in the loops between the two axons. Two segments form a loop with a delay line of 4 msec. The frequency of repetition is about 250/second. Each additional segment introduces another delay of about 4 msec. For a three‐segment loop the repetition rate is about 125/second. The delays at ephaptic junctions between neurons in vertebrate nervous systems are probably too brief to cause repetitive activity.
Renal transport of glucose by the aglomerular fish Lophius americanus
Authors: Malvin Richard L. , Cafruni Edward J. , Kutchai Howard
Published: February 2005

The renal excretion of glucose by the aglomerular fish Lophius americanus was studied. It was found that glucose is a normal constituent of Lophius urine. U/P ratios were approximately 0.02. However, after elevation of plasma glucose level or injection of phlorizin the U/P ratio for glucose was increased as much as ten fold. This increase in U/P ratio was observed even if urine was collected directly from the ureter rather than from the bladder. These results are consistent with the hypothesis that glucose is able to diffuse across the renal tubular epithelium, which also has the ability to reabsorb glucose which diffuses into the urine.
Oxygen consumption, thermal conductance, and torpor in the California pocket mouse Perognathus californicus
Authors: Tucker Vance A.
Published: February 2005

Non‐torpid P. californicus have body temperatures which increase slightly as ambient temperature increases from 5° to 35°C. Their minimum oxygen consumption fits Newton's law of cooling, since minimum thermal conductance below thermal neutrality is virtually constant at 0.19 ml O2 (gm hr °C)−1. There is a thermal neutral point at 32.5° rather than a thermal neutral zone. Oxygen consumption at the thermal neutral point is 0.97 ml O2 (gm hr)−1. Maximum thermal conductance, measured at 35°, is 0.37 ml O2 (gm hr °C)−1. Evaporative water loss accounts for 5 and 15% of the value of minimum and maximum thermal conductance, respectively.

Minimum oxygen consumption of mice in torpor is continuously dependent on body temperature from thermal neutrality to deep torpor. Q10 values are between 1.6 and 3.2. The thermal conductance of torpid mice at ambient temperature below 30° is 0.19 ml O2 (gm hr °C)−1 which is identical to the minimum thermal conductance of non‐torpid mice. Torpid mice at an ambient temperature of 30° have thermal conductance values between 0.23 and 0.40 ml O2 (gm hr °C)−1 depending on their posture.

Maximum oxygen consumption is linearly related to body temperature. At a normal body temperature of 38°, it is 11.6 ml O2 (gm hr)−1 which is no greater than that of similar sized mammals which do not enter torpor.

Although P. californicus consistently enters into and arouses from torpor at ambient temperatures of 15° to 30°, the torpor cycle is severely disturbed at temperatures between 10° and 12°. At these temperatures mice show irregular temporal patterns of torpor, do not enter torpor completely, and cannot arouse from torpor if body temperature falls below 15°.

Observations on the behavior of torpid and non‐torpid P. californicus at various ambient temperatures are included in this report.
Comparative carbohydrate catabolism and methemoglobin reduction in pig and human erythrocytes
Authors: Rivkin Saul E. , Simon Ernest R.
Published: February 2005

Pig red cells were characterized structurally and chemically, the rates of certain of their carbohydrate metabolic pathways were determined, the capacity to utilize these pathways for methemoglobin reduction was measured, and the results were compared with similar studies in human erythrocytes. Pig cells are smaller, contain less hemoglobin but are similar to human cells in mean cellular hemoglobin concentration. Unlike most other mammalian red cells, including human erythrocytes, pig cells are glucose “free” or nearly so; plasma concentrations of glucose are similar in both species. On a per cell basis, the content of adenosine triphosphate and reduced glutathione is similar in both species. Pig red cells catabolize glucose at about one‐tenth the human rate; for each mole of glucose consumed, two moles of lactate are formed. In both species, a similar proportion (5 to 10%) of the total glucose catabolized passes via the phosphogluconate oxidative pathway. Both species form lactate from inosine at similar rates; the pathways involved appear similar. Pig hemolysates prepared in water form lactate from glucose, glucose‐6‐phosphate, or inosine; freeze‐thawing destroys this potential. Methemoglobin reduction rates of red cells suspended in plasma are similar in both species. With human cells the plasma glucose concentration accounts for the rate; with pig cells, the lactate level appears responsible. Cells of both species apparently link methemoglobin reduction to reduced diphosphopyridine nucleotide generated via Embden‐Meyerhof glycolysis but can couple reduced triphosphopyridine nucleotide, generated via the phosphogluconate oxidative pathway, to methemoglobin reduction as well.
Oxidation of cholesterol by rat liver mitochondria: Effect of thyroidectomy
Authors: Kritchevsky David , Tepper Shirley A.
Published: February 2005

Normal and thyroidectomized rats were maintained on normal diets and on diets containing 0.3% N‐propylthiouracil. The normal rats on normal diets had significantly lower serum cholesterol levels than did any of the other groups. Liver cholesterol levels were elevated only in the thyroidectomized rats fed normal diet. The hypercholesteremic effect of N‐propylthiouracil observed in the thyroidectomized rats appears to be due to release of liver cholesterol.

Liver mitochondrial preparations from all four groups of rats oxidized cholesterol‐26‐14C and sodium octanoate‐1‐14C to 14CO2 to the same extent. The data further support the hypothesis that the effect of thyroid on cholesterol degradation is mediated at the level of nuclear hydroxylation.
The exchange of C14 glucose across the membrane of the human erythrocyte
Authors: Mawe R. C. , Hempling H. G.
Published: February 2005

We have measured the equilibrium efflux of C14 labeled glucose across the cell membrane of the human erythrocyte under conditions when glucose was present in equal concentrations on both sides of the cell membrane, and also the net efflux of C14 labeled glucose from glucose‐loaded cells into a large extracellular environment that contained no glucose. A method of ultrafiltration through millipore filter discs was developed to obtain samples of medium during the loss of cell isotope to a medium free of isotope. Fluxes with half times as low as five seconds could be determined accurately and reproducibly. With this method we have extended the observations of other workers down to glucose concentrations of 0.03 M and found as others had previously that the half time for tracer exchange would decrease with a decrease in the equilibrium glucose concentrations. Further, by measuring equilibrium fluxes and maximal net fluxes of cells from the same blood sample, we have obtained evidence that the carrier laden with glucose is transported more rapidly than the free carrier.
The effect of peritoneal fluid on glucose‐U‐C14 oxidation by rat peritoneal leukocytes
Authors: Hrachovec Josef P.
Published: February 2005

The rate of C14O2 evolution from uniformly labeled glucose by washed white cells from peritoneal exudates increased several times after prolonged soaking of the cells in protein‐free medium and was repressed again upon incubation of the cells in peritoneal fluid of higher concentrations, whereas incubation in lower concentrations had a stimulatory effect, as compared to this rate by the cells incubated in protein‐free medium alone. Similarity of this effect of peritoneal fluid to the protective action of blood serum on the cells in tissue culture and the possible mechanism of action of both were discussed.

It is suggested that the metabolism of the cells in multicellular organism is repressed by humoral macromolecular substances, and that the increase of glucose‐U‐C14 oxidation by the cells after prolonged soaking in protein‐free medium is related to the first step in the processes by which the cells move from a dormant state in vivo into that of active growth and cell divisions in vitro.
Transformation of hamster embryo cells in vitro by polyoma virus: Morphological, karyological, immunological and transplantation characteristics
Authors: Defendi V. , Lehman J. M.
Published: February 2005

The transformation process induced by polyoma virus in mass cultures of hamster embryo cells has been analyzed chronologically for several parameters: morphology, karyology, antigenicity and transplantability. Morphological changes, as manifested by the altered growth pattern of the culture, were the first indication of transformation. The expression of morphological transformation differed among colonies from a single culture and among the various cell lines; its pattern could change with prolonged growth of the cultures. Established lines originating from each transformed culture eventually produced tumors in syngeneic and allogeneic animals. Tumorigenicity was low (MTD ± 106) soon after morphological transformation, but increased progressively as the cells were carried in vitro (MTD < 103). Polyoma virus disappeared in eight lines, but persisted in one. The non‐virus releaser lines were resistant to superinfection with polyoma virus. The polyoma‐induced transplantation antigen (PV‐ITA) was found in four of six lines; it was not demonstrable in later passages of some lines that were initially positive and was not detected in the virus carrier culture. The polyoma‐induced CF antigen (PV‐ICFA), however, was present in all the cultures exposed to polyoma virus even at passage levels where the PV‐ITA was not demonstrable. Some chromosomal changes in type and in ploidy were present at, or shortly after, the time of morphological transformation. Although very low at first, frequency of chromosome changes increased with time in a random pattern. Three of four lines remained near‐diploid, the fourth line became subtetraploid soon after morphological transformation. The incidence of chromosomal damage (chromatid breaks, dicentrics and fragments) was low in all four lines analyzed, even in the virus carrier culture. There was a parallel increase in frequency of abnormal metaphases and of transplantability.

It is concluded that after an initial and yet obscure polyoma virus cell interaction, cells evolve toward malignancy in a pattern that does not show specificity for the inducing virus. The viral genome, if present in the transformed cells, does not appear to direct or regulate the evolution of the cells in vitro.
On the homology of the cranial muscles of the cypriniform fishes
Authors: Takahasi Nisuke
Published: February 2005

Much more information than is available at present must be obtained before the phylogeny of the muscular system in the Teleostei can be worked out satisfactorily. As a step toward the solution of this problem, the present study gives a detailed description of twenty cranial muscles in a number of species belonging to three groups of cypriniform fishes: the Cyprinoids, Cobitoids, and Siluroids.

Particular attention is given to the morphological relations of the following muscles: adductor mandibulae, geniohyoideus, levator arcus branchialis, adductor arcus palatini, retractor branchialis dorsalis, interarcualis dorsalis and the trapezius.

Comparison is made between corresponding muscles in different members of the three groups of fishes, and various homologies are pointed out between muscles in cypriniform and those in other fishes, especially Amia, Scomber, Perca and Esox.
Nervous system of the earthworm, lumbricus terrestris L.
Authors: Hess Walter N.
Published: February 2005

A study of the peripheral nerves of the earthworm shows that one pair of nerve trunks arise from the lateral regions of the cerebral ganglion, one pair from near the lateral, and two pairs from the ventral region of the circumpharyngeal connectives. These supply, in the order given, the prostomium, segment 1 and segment 2. Segment 3 and each succeeding segment, except the last, are supplied with three pairs of nerve trunks which arise from the nerve cord in the segment concerned. None of the nerve trunks of the body was observed to send branches to more than one segment, which shows that they are segmental in origin and distribution.

The anterior portion of the central nervous system has undergone caudal migration and modification of its ganglia. Some of the nerve trunks have disappeared through atrophy, while others have become fused at their bases.

A subepidermal nerve plexus is found at the base of the epidermal cells from which nerve fibers pass to the internal nerve net and to the central nervous system. This plexus also sends intercellular and intracellular fibers into the epidermis.

The so‐called sense cells of the epidermis appear to be the cell bodies of sensory neurones which send nerve fibers to the ganglia of the central nervous system, where they form synaptic connections with other neurones.

There is an enteric nerve plexus in the wall of the alimentary canal which is directly connected to the circumpharyngeal connectives.
Karyosphere formation and synapsis in the beetle, phanaeus
Authors: Hayden Margaret A.
Published: February 2005

The parasynaptic union of chromosomes associated with the formation of a karyosphere is demonstrated in the spermatocytes of Phanaeus.

The twelve V‐shaped leptotene threads are polarized with their apices embedded in one plasmosome‐like body, their distal ends in another (primary and secondary caps, respectively), and undergo a conjugation of the parasynaptic type. The distal ends of the chromosomes are freed from their attachment in the secondary cap. The six pachytene loops retain their polarized configuration.

The basichromatin of the pachytene chromosomes appears ultimately to be withdrawn to form the karyosphere comprising six chromatic bodies within an oxychromatic «plasmosome,» the latter probably derived from the primary cap. The two caps are believed to arise from the chromosomes. The primary cap apparently becomes incorporated again in the chromosomes; the secondary cap, together with linin remnants of the pachytene chromosomes, disintegrates in the nucleus as residual chromatin.

In the dissolution of the karyosphere six ring‐shaped tetrads emerge arranged in a temporarily connected chain, giving under certain conditions, the misleading impression of twelve components arranged end to end. The entire content of the karyosphere appears to be employed in the formation of the chromosomes; no visible plasmosome remains.
The development of the trunk and tail lymphatics and posterior lymph hearts in anuran embryos
Authors: Kampmeier Otto F.
Published: February 2005

This paper represents the third part of a monograph on the development of the lymphatics and lymph hearts of Anura. In this part are considered the origin and development of the subvertebral, lateral, and dorsal lymphatics of the trunk, the caudal lymphatics, and the posterior lymph hearts.

The chief lymphatic trunks arise along the veins from a series of small, spindle‐shaped, and discontinuous anlagen which subsequently coalesce and thus establish continuity with one another. Lymph plexuses are formed from which emerge the main secondary lymph channels. After such trunks are laid down as indicated, smaller branches and capillaries spring from them by sprouting or extension, due to their actively proliferating endothelium.

The posterior lymph hearts ‘crystallize,’ so to speak, from localized areas of the lateral lymphatic plexus. During its reorganization and differentiation, it temporarily separates from the surrounding lymph plexus. Other genetic details, such as the formation of its valves, histogenesis of its walls, number of hearts laid down, etc., are also considered. Twenty‐two figures (microphotographs and reconstructions) accompany the text.
Studies on the physiology of the liver VI. The effect of total removal of the liver in lower vertebrates
Authors: Magath Thomas B. , Mann Frank C.
Published: February 2005

The effect of removal of the liver has been noted in fishes, frogs, and turtles. As in the higher vertebrates, removal of the liver produced a fall in blood sugar and a loss in muscular tone. The lower vertebrates failed to respond to intravenous injections of glucose, as do the birds and mammals. They also fail to respond to maltose or levulose. The liver maintained the blood‐sugar level in the lower vertebrates, which is necessary for the maintenance of life.

The mechanism of carbohydrate metabolism in the lower vertebrates may be different from that in the higher ones, in that glucose, when injected intravenously, apparently exercises a progressively less beneficial effect on the characteristic hypoglycemic condition which follows the removal of the liver of mammals and cold‐blooded vertebrates.
Natural partial fertilization in fasciolaria
Authors: Hyman O. W.
Published: February 2005

Of the eggs laid by Fasciolaria about 1 per cent develop into veligers, about 2 per cent more undergo a few cleavage divisions, and about 97 per cent do not divide at all. The 99 per cent that fail to develop normally are ‘swallowed’ by the veligers. This study concerns itself chiefly with the ova that do not divide. Notes on normal development and on the ova that undergo atypical cleavage are included.

All of the ova are found to be typical when passed from the ovary. To each ovum one to several sperms become attached at the vegetal pole in the region of a mass of undifferentiated protoplasm—the ‘polar mass.’ A fertilization cone forms in each ovum and a fertilization membrane. In typical development a yolk lobe is formed, the sperm enters in the usual way, and fertilization is completed as in many other mollusks. In 97 per cent of the ova the yolk lobe is not formed and the sperm does not enter. In these cases the wall of the egg nucleus remains intact a long time. The nucleus itself and the ‘polar mass’ sink into the egg and meet at the center. Then the nuclear wall disappears and an atypical diaster is formed. However, cleavage is not begun and the chromosomes form vesicles that remain near the center of the ovum until it is ‘swallowed’ and digested by the veliger.
Development of the pelvic fins of acipenser ruthenus. New data for the theory of the paired fins of fishes
Authors: Sewertzoff A. N.
Published: February 2005

The pelvic fins of the ancestors of the Chondrosteoidei possessed a metameric musculature and their skeleton consisted of a large number of metamerically arranged cartilaginous fin‐rays, to which were attached osseous lepidotrichia. Evolution has involved the concrescence of separate elements to form the basal cartilage, the proximal end of which forms the girdle of the fin; the loss of a number of the fin‐rays, and the atrophy of distal elements of the rays. The adult Chondrosteoidei have retained the primitive fin structure which characterized the elasmobranchs of the Palaeozoic period and which has disappeared in recent forms.
Molgula citrina (Alder and Hancock). Activities and structure of the free‐swimming larva
Authors: Grave Caswell
Published: February 2005

The activities of the larva and the responses and orientations it makes to external stimulation, and the structural organization by which these activities are produced, are described and figured.

Existing systematic confusion of M. citrina with other species (M. manhattensis, M. nana, and M. microsiphonica) is cleared. The duration of the period of larval life is found to vary between 5 and 170 minutes. A proportionally small number retain the larval form a longer time. During larval life, periods of swimming movements alternate with periods of inactivity, the latter, at first of momentary duration, becoming longer and longer until activity ceases.

No light receptor exists and no response to light is made. A statolith is found in the sensory vesicle, and frequent geonegative orientations are made during the free‐swimming period. These are of short duration and tend to occur, 1) when it emerges from the parent; 2) at the beginning of each of the frequently recurring periods of swimming activity; 3) immediately upon making contacts. Unoriented movements follow each orientation and constitute much the greater part of behavior.

The larva lacks definite organs of attachment. The entire surface of the tunic becomes adhesive at the time of metamorphosis. Only those structures that make up the action systems of the larva are fully differentiated, all other parts are embryonic in condition.
The regulation of skin‐pattern in an amphibian, Diemyctylus
Authors: Collins H. H. , Adolph E. F.
Published: February 2005

The integument of the vermilion‐spotted newt contains three kinds of pigment‐–yellow, red, and black. The yellow is uniform and continuous over the whole body; the red and black are discrete, and are chiefly in large spots. The pattern does not change measurably in an adult individual.

Functional changes in contraction of the scattered dorsal melanophores were uncommon. The only efficient single factors found were a long subjection to low temperature (expansion) and injection of pituitrin (contraction).

Removal of skin was followed by a rapid mass migration of dermal elements into the wound area. Melanophores were thus furnished to a dorsal wound, and after several months black spots formed from these. Red pigment never regenerated nor migrated into a wound. Yellow pigment was formed in situ after the wound had completely healed.

Auto‐, homo‐, and heterotransplants lost their pigment patterns and were gradually reorganized so as to conform in gross appearance to the surrounding pattern of the individual host's skin. The transformation was never complete in eight months, but new black spots and new yellow pigment eventually formed.

The behavior of melanophores during morphogenesis differed for specific areas of the integument. Their movements and aggregation were highly coordinated among themselves.
Cell division and ciliogenesis in the ciliated epithelium of the pharynx and esophagus of the tadpole of the green frog, Rana clamitans
Authors: Kindred James E.
Published: February 2005

All phases of mitosis have been observed in the ciliated cells of the pharynx and esophagus of the tadpole of the green frog, Rana clamitans. Centrosomes have been observed in ciliated cells. These data contravene the hypothesis of Lenhossék and Henneguy to the effect that ciliated cells cannot divide by mitosis because they have lost their centrosomes in the formation of the basal corpuscles to which the cilia are connected, and the corollary to this hypothesis (Jordan, '13), that in consequence ciliated cells must divide by amitosis. From counts of cells with cilia, those without cilia but with basal corpuscles, and those without either cilia or basal corpuscles in different phases of mitosis, it is inferred that the cilia are lost during mitosis.

Cilia sprout from basal corpuscles, and not from mitochondria in cells undergoing ciliogenesis. From the presence of diplosomes in the distal region of cells in which basal corpuscles are developing, it is assumed that the basal corpuscles arise by partition of the centrosome of the preciliated cell. The centrosome, however, does not become completely lost by reason of this process, but retains enough vitality to insure mitosis. Amitosis, which occurs in some of the ciliated cells, results, according to these data, from degree of differentiation, not from structural deficiency.
Some cytoplasmic structures in the male germ cells of gelastocoris oculatus (Toad bug)
Authors: Payne Fernandus
Published: February 2005

The chondriosomes are first recognizable as two clusters in contact with the nuclear wall. Beneath each cluster lies a chromosome. This relationship is constant and indicates that these two chromosomes play a part in the growth and development of the chondriosomes. The two masses fuse and the single mass grows considerably during the early growth period. Later it breaks up into a number of threads which become rings in the late growth period. The rings fuse into the large nebenkern which plays the usual rôle in the formation of the tail.

The Golgi material is first seen outside of the chondriosomal cap. Early in the growth period, it breaks up into Golgi bodies which remain distributed in the cytoplasm during the growth period and spermatocyte divisions. About the midgrowth period a large number of spheres suddenly arise. Since they later fuse to form the idiosome, they are called the proidiosomal spheres. These spheres, which may originate in the Golgi bodies, remain scattered in the cytoplasm during the growth period and spermatocyte divisions. In the spermatid the Golgi bodies collect about the idiosome to form the acroblast. The Golgi remnants pass into the cytoplasm of the tail, while the acrosome elongates into a tail‐like structure at the anterior end.

The centriole was followed with unbroken continuity from the midgrowth period into the middle‐piece of the sperm.
The chromosomes of clypeaster rosaceus
Authors: Gardiner Mary S.
Published: February 2005

The diploid number of chromosomes obtained from counts of anaphases of the first somatic mitosis is found to be forty‐four. Of these, seven have terminal, thirty‐seven non‐terminal attachment, giving a distribution of seven rods, thirteen V's, and twenty‐four J's. The number is constant in all the fertilized eggs counted, indicating an XX–XY arrangement of the sex chromosomes.
The significance of hemal nodes
Authors: Jordan H. E.
Published: February 2005

The investigation is based upon hemal nodes of dog, man, and sheep. The material can be arranged in a regressive series leading from a typical lymph node, except for the occurrence of blood in parenchyma and sinuses, to a lymphoid structure at a late stage of involution. These structures uniformly lack lymphatics. There is no evidence of direct luminal connection between the blood‐vascular supply and the sinuses. The observation that certain cervical and subcutaneous lymph nodes of the rabbit undergo a myeloid metaplasia following atrophy and disjunction of their lymphatics is used as an explanatory key of hemal nodes. According to our view, hemal nodes represent stages in the involution of transient lymph nodes. Disjunction of the lymphatics leaves the sinuses filled with entrapped lymphocytes. These differentiate into erythrocytes. These red blood cells may disintegrate and pass into solution or be removed either by giant cells or mononuclear phagocytes. Late stages in this process are represented by small irregular masses of lymphocytes, with wide sinuses practically free of blood.
Parental chromosome dimensions in Ascaris. A study of the effect of cellular environment on chromosome size
Authors: Hance Robert T.
Published: February 2005

In the early cleavage stages of Ascaris the homologous chromosomes are of unequal length. Measurements show that these homologues fall into two sharply defined groups suggesting their biparental origin. The shorter are considered to have come from the male.

As the age of the embryo increases, these differences between the chromosome mates tend to become less, and it is suggested that at some later period in the history of the animal this difference will entirely disappear in response to the effect of continued existence in a common environment. The length of the chromosomes is very slightly shortened during the early cleavage divisions, while the area of the equatorial cross‐section of the cells becomes enormously reduced.
The exoskeleton as a factor in limiting and directing the evolution of insects
Authors: Kennedy Clarence Hamilton
Published: February 2005

Each step forward in the evolution of new organs or new abilities has made possible further evolution, but at the same time has set up mechanical and physiological conditions that place definite limits on the future possibilities of evolution. The exoskeleton has made possible very definite advances in the evolution of insects, but at the same time has limited their evolution in fully as many other ways.

Opportunities in evolution opened up by an exoskeleton are its use as armor, as a skeleton, in the development of wings, as protection against desiccation. It has conditioned small size opening up numerous limited environments, increasing mutability due to short life. It conditions a tracheal system which speeds metabolism, and a variety of specialized mouth parts as well as locating the sense of smell on the surface where it is more effective. Metamorphosis evolved from ecdysis.

Limitations imposed by an exoskeleton are small size, simple nervous system due to small size, short life preventing education, inflexible societies due to simple nervous system, cold‐bloodedness, clumsy appendages, loss of closed blood system, excretory system reduced to malpighian tubules, poor development of touch and hearing and mosaic vision.
A neuromotor apparatus in the ciliate Dileptus gigas
Authors: Visscher J. P.
Published: February 2005

A system of fibers has been found in Dileptus gigas which is probably a neuromotor apparatus. A distinct elongated basal rod, found near the base of the gullet, gives rise to three sets of fibers: (1) a set of heavy fibers radiates out around the funnel‐shaped gullet; (2) a pair of heavy fibers pass directly from the basal rod to the band of trichocysts, one on each side, extending to the tip of the proboscis; (3) a set of very delicate branching fibers is distributed over the surface of the organism.

This system of fibers is held to be a neuromotor apparatus, because, (1) the general structure and appearance of the fibers suggest a neuromotor function and, (2) there is little or no evidence indicating any other function; and because, (3) the fibers in this system are connected to the most highly specialized structures in Dileptus, and, finally, because, (4) they are similar to structures found in other forms for which a neuromotor function has been experimentally demonstrated.
Conjugation in the ciliated protozoon, Dileptus gigas, with special reference to the nuclear phenomena
Authors: Visscher J. Paul
Published: February 2005

In conjugation fusion occurs along the entire oral surfaces of the proboscides of Dileptus gigas. Two size‐reducing divisions occur in rapid succession immediately preceding conjugation. Only one of the many micronuclei takes part in the process of nuclear reorganization. All other chromatic material is massed at this time in the posterior portions of the conjugants. The pronuclei are derived from the single active micronucleus, and interchange occurs immediately preceding the separation of the mating individuals. The fertilization nucleus divides to form two nuclei of diverse size. The smaller one produces thirty‐two or sixty‐four micronuclei, while the larger one divides to produce a like number of macronuclei, each of which finally breaks up into many chromatic granules which form the numerous densely staining nuclear derivatives which are characteristic of the vegetative stage of Dileptus gigas.

In the early stages of this reorganization process specimens are frequently found with from two to eight distinct nuclei often arranged in a series as in a beaded nucleus. This condition probably explains the frequent references in literature regarding such a nuclear condition in Dileptus.

Dileptus gigas has, accordingly, in the vegetative stage, a multinucleate condition with reference to the micronucleus and a fragmented or distributed condition with reference to the macronucleus.
Developmental modification and elimination of the larval stage in the ascidian, Corella willmeriana
Authors: Child C. M.
Published: February 2005

The eggs of Corella develop in the atrial chamber of the parent at a pH below that of normal sea‐water (pH 7.4 ±). When removed to normal sea‐water in early stages and under certain other experimental conditions, larval development is more or less inhibited, the tail being most inhibited, the dorsal region somewhat less. The free larval stage may be eliminated and later development and metamorphosis may proceed normally to an advanced stage in the chorion and give rise to normal ascidians. The region most inhibited are, in general, those which possess the highest reducing power, as indicated by KMnO4. Experiments made in the attempt to control development all agree in indicating that the early stages are adjusted to a certain CO2 concentration approximately that of the atrial chamber and presumably near that of the body. Solutions of the same pH may or may not inhibit development according to their CO2 content.

The tail, the region of highest reducing power in the embryo during its development, is most inhibited; the dorsal region, the next most rapidly reducing region, is next in degree of inhibition. All differences in reducing power disappear when, or soon after, the animals are killed by other agents before treatment with KMnO4.
A comparative study of the chromosomes of the Norway rat (Rattus norvegicus ERXL.) and the black rat (Rattus rattus L.)
Authors: Pincus G.
Published: February 2005

By the use of a satisfactory technique, excellently preserved spermatogenetic tissue was had both for Rattus rattus and Rattus norvegicus. The careful examination of twelve spermatogonial cells of the former species and of twenty in the latter species shows that R. rattus has forty diploid chromosomes and R. norvegicus, forty‐two. A careful examination of the haploid cells of both species, both in the first and in the second spermatocyte divisions, confirms the diploid determinations.

Both species have an unequal pair in the spermatogonial divisions and the finding of a similar unequal pair in the first spermatocyte division constitutes the evidence for an X‐Y mechanism in each. A comparison of the morphology of the first spermatocyte tetrads in the two species reveals the presence of a large K‐shaped chromosome in R. norvegicus which is not present in R. rattus. Furthermore, a comparison of the X‐Y complex in both the spermatogonial and first spermatocyte divisions shows that these are morphologically different in the two species, the Y in particular being markedly dissimilar in size. A short discussion as to the bearing of these findings on the questions of the origins of the two species and their known intersterility is presented. The marked similarity of the tetrads of the black rat to those described for the mouse is noted.
The digital pads of the tree frogs. A study of the phylogenesis of an adaptive structure
Authors: Noble G. K. , Jaeckle M. E.
Published: February 2005

The digital disks of the tree frogs are covered ventrally with a superficial layer of vertically elongated, fibrous, and distally free cells between which there empty a series of convoluted mucous glands. The latter are surrounded and, in the larger‐disked species, divided into blocks by sheets of collagenous fibers. The glands are emptied by the squeezing together of the collagenous fibers when the body weight exerts a pull on the terminal phalanges. The disks function by friction, cohesion, and adhesion.

The digital‐disk apparatus was fully established before certain groups of frogs became arboreal. It is retained in others which have reverted to the terrestrial habit. The intercalary cartilage increases the efficiency of the apparatus. It did not arise in phylogeny until after the apparatus was developed.

As the digital disks vary in extent in both arboreal and terrestrial species, arborealism seems to have resulted from a chance occurrence of large disks in the smaller‐bodied forms; at least, there is no progressive modification of the digits toward particular habitat requirements.

The subarticular tubercles of many Salientia develop typical climbing apparatus. This may or may not be correlated with an arboreal habit. In the species with the largest subarticular tubercles no apparatus is present. Arboreal salamanders exhibit no special climbing mechanism, but adhere by pressing their moist integument against the substratum.
Spermatogenesis of Bruchus quadrimaculatus (Coleoptera: Bruchidae)
Authors: Brauer Alfred
Published: February 2005

Notwithstanding the fact that several species of Bruchidae have been used by geneticists for several years, no cytological studies have as yet been made on any member of this family of the Coleoptera. The present paper gives a general account of the spermatogenesis of Bruchus quadrimaculatus Fabr.

The spermatogonia undergo two mitotic divisions. After the second division, the nuclei remain small and very dense for some time before the beginning of the growth phase. During this interval the nuclei do not assume again the characteristics of the interkinesis stages. In the primary spermatocytes typical tetrads are formed. The chromosomes are asymmetrically V‐shaped. The end of one arm of the ‘V’ fuses with the end of the corresponding arm of its synaptic mate. Disjunction takes place in the primary spermatocyte division. After the division of the secondary spermatocytes, the chromosomes become vesicular and form a reticular nucleus in the spermatid, after which the chromatin becomes deposited as a chromatin rim around the nuclear periphery. The diploid number of chromosomes is nineteen in spermatogonia and in male somatic cells, and twenty in female somatic cells. An unpaired X chromosome is present in the spermatogonia, which fails to divide in the primary spermatocyte division, but passes as a whole to one pole in advance of the autosomes. The X chromosome divides normally in the secondary spermatocyte division with the autosomes.

In the method of sex determination, Bruchus does not follow the method of the majority of beetles, since most of those studied adhere to the X‐Y type.
The spermatogenesis of lebistes reticulatus
Authors: Vaupel Jean
Published: February 2005

The germ cells of Lebistes are found in cysts; the younger cysts are toward the cortex. Mitochondria and Golgi apparatus are present. During maturation leptotene, bouquet, pachytene, and diakinesis figures are seen. The spermatocyte chromosomes number twenty‐three; an X‐Y pair is probably present, though the evidence is not conclusive. In spermatid formation the centriole divides to form a rodlet and an axial filament; the nucleus segregates into two materials, one of which is extruded; the remainder first contracts to a cup, comes in contact with the rodlet, then again forms a sphere. The mitochondria are arranged along the proximal part of the axial filament; the sphere flattens and elongates; the rodlet sinks into the head substance and is enfolded by it. The Golgi remnant is sloughed off with the residual cytoplasm, which disappears at the same time the Sertoli cells show an increase in size, suggesting their ingestion of the spermatid remnants. The mature sperm form spermatozeugmen, which are stored in the testicular canal; they are transferred to the female by aid of the modified anal fin.
Studies in the origin of yolk. IV. Ogenesis of Periplaneta americana
Authors: Nath Vishwa , Mohan Piare
Published: February 2005

Technique. This work is based not only on the fixed preparations, but also on fresh cover‐slip preparations treated with neutral red or 2 per cent osmic acid for a short time.

Golgi elements and fatty yolk. The Golgi elements are hollow vesicular bodies with a distinct osmiophilic rim and a central osmiophobic substance. In the youngest oocyte they form a circumnuclear ring. Gradually the vesicles spread out, grow in size, store up fat in their interior, and give rise to the fatty yolk. On account of their higher refractive index, due to the presence of fat, the Golgi vesicles can be occasionally seen even in the young oocytes without any treatment.

Mitochondria. The mitochondrial granules also form a circumnuclear ring and are later distributed uniformly.

Albuminous yolk. The albuminous yolk is nucleolar in origin. Early in oogenesis, the nucleous buds off small, homogeneous, and highly chromatic particles in the cytoplasm, which sooner or later disappear. Subsequently, the nucleolus becomes less chromatic and develops vacuolar bodies in its interior, which, becoming vacuolated exactly like the parent nucleolus, migrate into the the cytoplasm. These bodies become more and more chromatic and travel toward the periphery of the egg, where they grow in size. Ultimately they break down into small, homogeneous, and highly chromatic bodies which are the definitive albuminous yolk spheres and which subsequently grow enormously in size.
The effects of the substratum, divalent and monovalent cations on locomotion in Amoeba proteus
Authors: Hopkins Dwight L.
Published: February 2005

The rate of locomotion in Amoeba proteus is dependent upon the nature of the substratum, the nature of the different divalent and monovalent cations present, and the ratio of the amount of the monovalent cations to the amount of calcium or strontium. Calcium is more efficient than strontium in antagonizing potassium. Magnesium and barium do not antagonize potassium. The four monovalent cations studied in antagonizing calcium are efficient in the following order: Na>K>Li>Rb. Calcium and potassium are more effective against antagonistic cations when combined with chlorine than when combined with phosphate.
On the statocyst of the American cephalopod genera
Authors: Ishikawa Masashi
Published: February 2005

From the structure of statocysts, in the so‐called phylogenetic tree of the Cephalopoda, the genus Scaeurgus is to be placed on the same branch as Polypus.

Meleagroteuthis has the same number of processes as Watasenia, Enoploteuthis, Abralia, Illex, and Stigmatoteuthis, which have ten processes, but in this genus the structure of statocysts seems to be tolerably well developed. For this reason, the author places this genus as a branch between Abralia and Illex.

Those three genera—Gonatus, Sthenoteuthis, and Onychoteuthis—which have eleven processes in a statocyst are to be placed in the same branch as Berryteuthis, Gonatopsis, Ommastrephes, Eucleoteuthis, Moroteuthis, and Symplectoteuthis, which have the same number of processes; of these, Gonatus, which has the most primitive structure of the statocyst, is to be put in the lowest position on that branch; but Sthenoteuthis, which has the same structure of the organ as Ommastrephes, is to be placed on the twig near Ommastrephes; and, lastly, Onychoteuthis has the same organ as that of Moroteuthis, which fact induces the author to set this genus in the position nearest to Moroteuthis.

The statocyst of Lolliguncula corresponds exactly to that of Loligo, which has twelve processes; this condition puts this genus on the same twig as Loligo.
The morphology of the palmar digital triradii and main lines
Authors: Wilder Inez Whipple
Published: February 2005

A study is made of the morphological types of the second, third, and fourth interdigital patterns of the human palm and their differential occurrence as a basis for determining the morphological significance of the digital triradii and main lines, which are the final remnants of the pattern boundaries. Certain types of patterns show a large preponderance, with a correspondingly large percentage of a certain morphological value for each digital triradius, although other morphological possibilities than the usual one are discovered in each case. Correlated combinations of rare patterns are presented and their hereditary nature discussed.
The histology of the blood of some bermuda ascidians
Authors: George W. C.
Published: February 2005

The structure of the living blood cells is described and the cells are classified in the following species of ascidians: Phallusia nigra, Ecteinascidia turbinata, Clavelina oblongata, Symplegma viride. Evidence for the genetio relationship of the various types of cells is discussed.