bluuebunny/crossref_metadata_2025_split huggingface dataset:
The use of cobalt salts as indicators of humidity and moisture
Authors: Solomon M. E. 
Published: February 2008

To meet the need for a simple method of measuring humidity in small spaces, a new method of using paper impregnated with cobaltous salts has been developed. Cobalt chloride paper is blue at low and pale red at high humidities, with a series of lilac colours between. There is a close correspondence between colour and relative humidity, although the colour is influenced slightly by temperature. It is shown that the colour is determined chiefly by the relative quantities of cobalt chloride and water in the paper. The paper is impregnated by dipping in a solution of CoCl2.6H2,O. The time required for a piece of CoCl2, paper to reach equilibrium with the atmosphere depends chiefly on humidity and temperature; up to 2 hr. exposure is allowed. Colour standards for the matching of test papers are prepared by exposing papers over constant humidity solutions and then sealing them up in liquid paraffin between opal and clear glass. It is possible to measure humidities from 40 to 70% R.H. to the nearest 2% R.H., and above this range to the nearest 5%, except for low humidities at low temperatures.Various colloid substrates other than paper, including mercerized cotton, cause the blue colour to persist at somewhat higher humidities; possible uses of this are suggested. Certain salts, such as potassium thiocyanate and sodium thiosulphate, produce a similar, but much greater effect, and also produce stronger colours. The method can thus be adapted for accurate use at higher humidities. Alternatively, the addition of zinc chloride or certain other salts adapts the method for use at low humidities.Papers more suitable for use at high humidities have been prepared with cobalt thiocyanate solution. A further improvement is the use of pure cotton tissue paper. Methods of impregnating the paper are described, also the above‐mentioned method of preparing standards. Approximate corrections for temperature are given. The influence of temperature and humidity on the time taken to reach colour equilibrium is described. An exposure of 30 min. is sufficient except at very high humidities, where up to 2 hr. may be necessary. Corrections are given for use when exposures other than 30 min. are allowed. The standards cover humidities above 50% R.H. at intervals of 5% R‐H.; teat papers can be estimated to about the nearest 1% R.H. But under unfavourable conditions, errors may amount to as much as ± 5% R.H., unless the corrections are used.
The effect of sulphanilamide and other bacteriostatic drugs on the growth of moulds
Authors: Snow D. , Watts P. S. 
Published: February 2008

Some fifty isolates of moulds, mainly Aspergillus spp. and Penicillium spp., were tested for their reaction to sulphanilamide, sulphonamide E.O.S., sulphapyridine, sulphamezathine, sulphaguanidine, propamidine and phenamidine.The moulds showed a high degree of specificity in their reaction to the drug concentrations: Aspergillus spp. were more susceptible to the drugs than were Penicillium spp. Most of the species included in the Aspergillus glaucus group were inhibited by concentrations of 1/8000 (125 p.p.m.) of sulphanilamide, sulphonamide E.O.S. or propamidine. Similar concentrations of sulphapyridine, sulphamezathine, sulphaguanidine and phenamidine had only a slight inhibitory effect on mould development. A. versicolor and A. sydowi showed very similar reactions to the drug concentrations, which is in keeping with their relationship on morphological grounds. In general, Penicillium spp. were not affected by small concentrations (1/2000 or less) of the drugs and were only partially inhibited by higher concentrations (up to 1/125) of sulphonamide E.O.S. Propamidine was more effective against certain Penicillium spp. though not all were susceptible. Some of the moulds were slightly stimulated by small concentrations of the drugs. No difference in the fungistatic effect of sulphonamide E.O.S. was apparent at different pH levels between 4 and 8.Different strains of the same species sometimes showed different degrees of resistance or susceptibility to the drug concentrations. This was particularly noted for strains of Aspergillus ruber, two of which showed marked resistance to propamidine when incorporated in beer‐wort agar while four other strains of the same species were susceptible to the drug when incorporated in this medium. The two resistant strains, however, were susceptible to propamidine when incorporated in the synthetic Czapek‐Dox medium.4 p.p.m. of p‐aminobenzoic acid was found to annul the fungistatic action of sulphonamide E.O.S. at concentrations of 250 p.p.m. The addition of p‐aminobenzoic acid to a synthetic medium incorporating propamidine did not annul the inhibitory action of this drug.
Certain aspects of resistance of plum trees to bacterial canker: Part III. The action of cell‐free filtrates of Pseudomonas mors‐prunorum Wormald and related phyto‐pathogenic bacteria on plum trees
Authors: Erikson Dagny , Montgomery H. B. S. 
Published: February 2008

A technique for introducing 2‐3 c.c. liquid into the bark of plum trees is described. Parallel injections with dyestuff throughout the spring failed to afford a reliable index of the invasive powers of the various test fluids introduced in this manner.A susceptible variety of plum (Giant Prune) showed greater injury by cell‐free filtrates of Ps. morsprunorum than did a resistant variety (Warwickshire Drooper), which showed negligible injury. The greatest injuries were caused by filtrates of cultures 5 weeks old, and over, especially when concentrated.Of other bacteria tested Ps. prunicola, Ps. syringae strains, Syringa 3, Ap. No. 1, Ap. No. 2, and Bact. pruni, yielded damaging filtrates, whereas Ps. syringae, strains pear 6 and 7, Ps. tabaci, Ps. fluorescens, Ps. marginalis, Ps. phaseolicola, Ps. tumefaciens, Ps. pisi and Ps. cerasi failed to do so.Some evidence is advanced for the view that the deleterious activity of Ps. mors‐prunorum may be due in part to an endotoxin of protein nature obtainable from the dried bacterial cells by acetic acid extraction.
Some causes of chlorosis and necrosis of sugar‐beet foliage
Authors: Hale J. B. , Watson M. A. , Hull R. 
Published: February 2008

The symptoms and characteristics of two virus and one fungus disease and four nutritional disorders of sugar beet which cause chlorosis and necrosis of the foliage are described. The causes of the diseases and methods of distinguishing between them have been investigated by analytical, pathological and field experimental methods.Experiments in which diagnosis was confirmed by serological and spectrochemical methods show that the two often easily confused diseases, sugar‐beet yellows virus and magnesium deficiency, can be visually distinguished.Sugar‐beet yellows virus reduces the potassium, but slightly increases the magnesium content of the leaves.Magnesium deficiency symptoms are associated with a low magnesium content of the foliage, but may be induced by salt applications without greatly affecting the magnesium analysis.‘Potash’ deficiency symptoms are often, but not necessarily, associated with a low potassium analysis and may actually be caused solely by a deficiency of sodium. In the field, symptoms are induced by sulphate of ammonia and phosphate applications and may be prevented in some cases by the application of either salt or muriate of potash, in others by salt only. Some interchangeability of the functions of potassium and sodium in the plant is suggested.Manganese deficiency symptoms are associated with a low manganese content of the leaves, which can be readily increased by spraying or injection with manganese sulphate solution, but a high concentration of manganese in the foliage, such as sometimes occurs naturally on acid soils, has a toxic effect.
Effects of atmospheric environment, before and after treatment, on the toxicity to insects of contact poisons. I
Authors: Potter C. , Gillham E. M. 
Published: February 2008

Experiments were made on the effect of conditions before and after treatment on the toxicity to adult Tribolium castaneum Hbst. of the following contact poisons in the media stated: (i) pyrethrins, (2) lauryl thiocyanate, (3) nicotine‐all in aqueous medium, (4) dinitro‐o‐cresol in ethylene glycol, (5) Wakefield half‐white oil, (6) D.D.T. in Wakefield half‐white oil.The difference in environment before spraying did not have any marked effect but, with the exceptions of nicotine and petroleum oil, all the toxicants used were more insecticidal when the beetles were kept under cool conditions after spraying. Nicotine showed little difference due to after‐treatment when an inverted filter funnel was used to confine the insects, but seemed markedly more toxic under cooler conditions of after‐treatment when the insects were confined in the dishes by means of muslin.Wakefield half‐white oil, a non‐volatile petroleum oil, proved more toxic when the insects were kept under warm conditions after treatment than under cool conditions. The increase in toxicity of chemically active contact poisons under cool conditions of after‐treatment appeared to occur whatever the nature of the carrier, whether volatile or non‐volatile, water or oil.In the substances tested, with the exception of nicotine under special circumstances, the increase in toxicity under cool conditions of after‐treatment occurred whatever the volatility of the poison.The change in toxicity, when cool conditions were compared with hot, varied with the poison used. With nicotine in aqueous medium the change was relatively small, the toxicity under cold conditions throughout being 1‐23 times the toxicity under hot conditions throughout. At the other extreme with pyrethrins and terpineol in aqueous medium there was a large alteration, the toxicity under cold conditions throughout being about 7 times the toxicity under the hot conditions throughout.
Diseases of the gladiolus III. Botrytis rot of conms and its control
Authors: Hawker Lilian E. 
Published: February 2008

The probability that the three types of corm rot of gladioli, associated with Botrytis spp., described by Moore (1939) are phases of the same disease is discussed.Control measures were of five types: (1) Measures to reduce the amount of active or dormant infection of the corms when lifted. Avoidance of heavy wet soil, ground in which gladioli had previously grown and shaded sites reduced the subsequent loss in storage. Relatively early lifting (during the first half of October) was beneficial. Rogueing of diseased plants during the summer and dusting of foliage with pentachloronitrobenzene dust (p.c.n.) gave some improvement, but further experiments are‐desirable. (2) Measures to reduce the development of the disease between lifting and storage. Early removal of adhering soil, cormels, roots, parent corms and old shoot and leaf bases (husks) gave good control. Rapid drying in warm, dry conditions was also beneficial, but washing the corms to remove soil was ineffective. Dusting with p.c.n. immediately after lifting and before cleaning gave a slight reduction in losses in two small‐scale experiments. (3) Pre‐storage fungicidal treatment of corms. Dusting with p.c.n. before storage gave good control, but almost complete control was obtained by steeping in a 01 % solution of mercuric chloride for 20 min. to 3 hr. This treatment has the advantage that it also controls hard rot (Septoria gladioli Passer.), scab (Bacterium marginatum McCull) and to a lesser extent dry rot (Sclerotinia gladioli Drayt.), but is liable to damage the corms. The safety limits are being worked out. (4) Conditions of storage. Corms should be stored in shallow trays in a dry, well‐ventilated shed, protected from frost. (5) Fungicidal treatment at planting time to protect the corm from soil infection. Mercuric chloride as a corm steep at this time gave only partial control, probably owing to rapid removal of the fungicide by leaching. Dusting with p.c.n. gave good results, not only in the protection of the old corm but in preventing infection of the new ones and the beneficial effect extended into the subsequent storage period. Soil treatment was not effective.
Further studies on the effect of disinfecting and bruising seed potatoes on the incidence of dry rot (Fusarium caeruleum (Lib.) Sacc.)
Authors: Small T. 
Published: February 2008

The effect on dry rot of the potato of disinfecting seed potatoes with a proprietary organo‐mercury fungicide immediately before they were clamped on lifting, and on their removal from the clamps after 3 or 6 months' storage, has been tested in field trials during two seasons. The incidence of the disease in tubers stored in clamps has also been studied. The tubers used were of the susceptible varieties Ninetyfold and Doon Star, taken from crops grown in contaminated soil. In certain of the tests the natural contamination in the soil adhering to the tubers was reinforced by spraying each tuber with a spore suspension of the dry‐rot fungus.Seed tubers not deliberately bruised on lifting, and whether dipped or not at that time, were practically sound after 3 and 6 months' storage in clamps except in one instance. On removal from the clamps, those not dipped on clamping continued to remain sound when carefully handled and stored for a further period in seed boxes, but they suffered either moderate losses if slightly bruised, or serious losses if severely bruised, at the time they were removed from the clamps. Tubers dipped immediately before being clamped yielded similar results, except that they remained sound when slightly bruised on removal from the clamps.Tubers not dipped, but deliberately bruised either on lifting in July immediately before clamping or on reclamping in October, developed severe dry rot whilst stored in the clamps. The incidence of the disease was not influenced by the location of the tubers within the clamp.In tubers not dipped at lifting and clamping time in July, but lightly bruised and immediately dipped on their removal from the clamps in October, the losses from dry rot were slight. Severe bruising followed immediately by dipping on their removal from the clamp in October, however, resulted in considerable losses.Tubers not dipped at lifting and clamping time in July but, after 3 or 6 months' clamp storage, slightly bruised and immediately dipped, then severely bruised 2 days later, developed appreciable losses; but these losses were far less than in tubers treated similarly except that the dipping was omitted.Tubers dipped on lifting immediately before clamping in July, and slightly bruised and immediately redipped on removal from the clamps in October, remained almost sound; but tubers severely bruised just before the second dipping in October developed a loss of 12%.All the foregoing results were obtained with tubers taken from healthy clamps. Ostensibly healthy tubers taken carefully from clamps containing much dry rot became severely affected with the disease when further stored in seed boxes.
Observations on the effects of browning (Polyspora Lini Laff.) of flax on seed production
Authors: Colhoun John 
Published: February 2008

An account is given of observations made on the effects on seed production of the incidence of the browning phase of the disease of flax caused by Polyspora Lini Laff. The work was carried out during three seasons.Disinfection of seeds before sowing exercises an effect on the average weight of the well‐developed seeds harvested, and the results obtained show that the intensity of the attack of browning in crops is inversely correlated with the weight of 1000 well‐developed seeds. When poorly developed seeds are separated from the remainder at harvest, evidence obtained in one year suggests that the percentage number of such seeds may be directly related to the incidence of browning in the crop. It was found in each of two years that more of the poorly‐developed than of the well‐developed seeds were contaminated with P. Lini. Evidence available for one year suggests that the viability of well‐developed seeds is not related to the incidence of browning.
The comparative toxicity of various contact insecticides to the louse (Pediculus humanus L.) and the bed‐bug (Cimex lectularius L.)
Authors: Busvine J. R. 
Published: February 2008

A variety of substances has been tested by laboratory methods as insecticides against the bed‐bug and the body‐louse. The oil‐soluble samples were tested by the Potter tower method which gave the most accurate results. Certain liquids were tested by a simple dipping method, and solids insoluble in mineral oils were tested as aqueous solutions by the dipping method or as dusts.Various organic thiocyanates were found to show similar relative toxicity to the louse and bug, but the pyrethrins were much more toxic to the latter. D.D.T. was highly toxic to both and Gammexane even more insecticidal, especially to the louse.In the dipping tests, two types of toxic action were observed: an immediate physicochemical action and a delayed lethal action due to asphyxiation. Refined mineral oils kill lice by the latter method. Among the aqueous preparations, the emulsion of cresols known as Lysol was noteworthy for its ovicidal powers.Some experiments were made with extracts of delphinium seeds, the insecticidal powers of which were shown to reside in the alkaloids.
Further investigations on the value of electric heating of beehives
Authors: Butler C. G. 
Published: February 2008

A set of twenty‐four colonies of honeybees was divided into three groups, two of which received different intensities of artificial heat, applied by means of specially designed heating frames placed in the middle of the brood chambers, from 2 Jan. to 16 Mar. 1942. Heating the colonies reduced the area of brood present at the beginning of May without noticeably affecting the consumption of carbohydrate stores and thus had an adverse effect on the colonies. This conclusion is in agreement with that reached as a result of earlier work (Butler & Cockbill, 1942.)Colonies in hives fitted with top entrances were no stronger in the spring than colonies in hives with bottom entrances, nor did they show any significant difference in store consumption.No significant brood chamber temperature differences were found in hives fitted with top entrances as compared with control hives which had normal bottom entrances.During the period when heat was applied to the colonies by means of the heating frames the minimum brood chamber temperature was significantly higher in the heated hives than in the control, unheated, hives, this being especially marked in the case of the hives fitted with 6 W. heaters.Throughout the experiment the minimum brood chamber temperature of all the hives showed a close dependence on screen temperature. During the preliminary period before the heat was turned on a change of 1d̀ C. screen temperature was associated with change of 0.92d̀ C. in the minimum brood chamber temperature in hives with top entrances, and a change of 0.86d̀ C. in hives with bottom entrances. After the heat was turned on the corresponding figures were 0.84d̀ C. for top entrance hives and 0.67d̀ C. for the bottom entrance hives.
The ecology and function of Protozoa in sewage purification
Authors: Neville A. , Barker M.Sc, Ph.D.  
Published: February 2008

Seasonal recording of the Protozoa in various sewage disposal units has shown that, together with changes correlated with the degree of purification of the sewage, fluctuations occur as a result of the interplay of seasonal non‐specific factors and local specific factors. The incidence and abundance of Protozoa in each disposal plant would seem to be controlled by sewage ‘strength’ and characteristic local drainage. Fluctuations of the population, however, are limited by different factors in different seasons.In the bacteria bed investigations a ‘weak’ sewage shows a decrease of a generally rich fauna during the periods of sloughing, a ‘strong’ acid sewage during sloughing shows an increase in an otherwise restricted fauna and where the sewage is medium in ‘strength’ and supports an abundant insect population the fluctuations of the Protozoa are dominated by the more active insect populations of summer and by temperature in winter. In this last‐named environment a significant inverse correlation between ciliate and insect frequency throughout the summer indicates the thoroughness with which the insect larvae devour the film; this may explain the summer reductions in certain groups of Protozoa.In activated sludge channels conditions favour a uniform population which may vary in composition according to the purity of the sewage. Flocculation is most pronounced when protozoan populations comprise a restricted variety of ciliates and would seem to depend on a protozoan fauna since cultures of bacteria obtained from sewage did not flocculate unless Protozoa, free from or contaminated with bacteria, were added.The protozoan populations of the two systems of disposal are compared in discussion.
Field trials of copper fungicides for the control of potato blight III. Low‐copper fungicides
Authors: Large E. C. , Beer W. J. 
Published: February 2008

In trials at Beaford, north Devon, and at Galmpton, south Devon, in 1945. proprietary preparations of copper oxychloride, cuprous oxide, and cuprammonium, used at low‐copper dosage (0.063 % Cu), were compared with Bordeaux mixture at the same and at higher dosages for the control of potato blight under two commonly recurring conditions of disease incidence, respectively early and late, which were closely defined by foliage decay curves.All the copper fungicides were tested with and without added adhesive of caseinate‐rosin soap type, and two sulphur fungicides: lime sulphur (1 in 50) and Dithane 14 (1 in 200) with zinc sulphate and lime, were also included.The trials were made on four‐times replicated plots at both centres; special precautions were taken to avoid confusion of the observations by concurrent mineral deficiency and virus disorders; and the treatments were compared by three criteria: (1) direct foliage protection, (2) spray retention and (3) indirect effect on yield. The number of spray applications was reduced to a minimum to avoid masking the superiority of the better treatments, and timed as nearly as possible for maximum effect in relation to weather conditions. Thus two applications were given at Galmpton and three at Beaford.None of the proprietary copper fungicides used at low‐copper dosage, with or without added adhesive, equalled plain (4.5.40) Bordeaux mixture in spray retention or direct protective effect; and none gave any significantly better protection than Bordeaux mixture at correspondingly reduced copper dosage (1.11/2.40).With the few well‐timed and thorough sprayings given, however, the 1% Bordeaux mixture itself gave almost sufficient protection for the production of a full crop, and the trials indicated horticultural conditions under which low‐copper fungicides can be used with success, while pointing to the important factor of safety secured by using 1 % Bordeaux mixture in routine agricultural practice.Both of the sulphur fungicides were less effective than i % Bordeaux mixture.