NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
14
2. Large rounded cells with extensive protoplasm and a round or oval
nucleus. Small specimens of these cells may give rise to a puzzling appearance
in films since they resemble, as far as the nucleus goes, a small mononuclear
leucocyte. The protoplasm is, however, much more extensive than is the case
with the leucocyte. Even large cells of this type are often seen whole or only
partially disrupted in films. Their protoplasm is often like ground-glass in
appearance and is usually vacuolated. Masses of the protoplasm of these cells
readily become separated from the cell (Pl. II. fig. 4), and may assume a globular
shape. They contain often 20 or more bodies. In sections of the testis and
of granulation tissue, cells which appear to be of this type are seen in the smaller
vessels attached as a rule by one side and projecting freely into the lumen.
Similar cells are seen in blood taken post-mortem from the large veins, femoral,
portal, hepatic. (Pl. II. figs. 7 and 9.)
3. In both the liver and spleen, immense numbers of very large cells are seen
lying in the capillaries. They may be extended along the capillary, or their
cytoplasm may be massed together. In the spleen, large cells are seen with long
processes extending in among the smaller cells of the pulp. Both types of cell
appear to be of the same nature. They have a single or double vesicular nucleus,
and their cytoplasm, which stains lightly, has numerous included bodies lying
either scattered more or less evenly throughout, or in groups.
4. In both the liver and spleen, but especially in the latter, extremely large
cells are seen in which the nucleus is small, stains intensely and is pushed to one
side or extremity of the cell. The cytoplasm of these cells stains more darkly
than does that of the last mentioned variety, and in some cases takes on a curious
dirty hue suggesting marked necrotic changes. The centre of the cell is occupied
by a large vacuolated space, and arranged around this are numerous parasitic
bodies. The cytoplasm of many of these cells is reduced to a mere pellicle con-
taining a crowd of parasites, and such cells appear to be on the point of rupture.
Cells of this and the last mentioned type are rarely seen whole in films unless
special precautions are taken by fixing in ¼ per cent. osmic acid. One such cell
in the bone-marrow contained as many as 250 bodies (Pl. II. figs. 10 and 11 ),
also (Pl. I. fig. 6).
Peripheral blood.—Laveran and Mesnil 3 record the presence of bodies in
the peripheral blood which they take to be endoglobular forms of the parasite.
Such forms, they say, are very rare, smaller than those found in the spleen and
have only one chromatin mass. I. have been unable to satisfy myself that un-
doubted bodies occur in the peripheral blood, free or in the red cell. Taking into
account the negative results of Manson and Low who examined a case with this
object very systematically and my own results on a number of cases, it does not
appear that typical forms are present. Laveran and Mesnil's forms do not appear
15
to me very convincing, and even these must be of extreme rarity. In two
advanced cases approaching a fatal termination, I have found in the peripheral
blood a considerable number of typical forms possessing double chromatin masses
and in every way resembling those found in the spleen, but these were all included
either in polymorphonuclear or mononuclear leucocytes. In one case 37
parasites, nearly all in polymorphonuclear leucocytes, were seen during a count
of 500 leucocytes. In the other case, 7 parasites were seen whilst counting a
similar number of leucocytes. In both cases leucocytes were in excess of the
number usually found in the disease in which, as a rule, the most marked leuco-
pœnia is found. In neither case did I find at this time free forms or forms in the
red cells. In several instances I have examined very carefully films of splenic
blood with a view to finding transitional forms between the bodies lying in a
matrix and those in unchanged cells, but unsuccessfully. I am led, then, to doubt
very greatly the specific nature of the bodies in the red cells.
In the most severe infections the relative leucocyte values do not appear to
shew very great changes. The leucopœnia is the most marked change, and this is,
as a rule, so great that it is necessary to take several large films in order to make
adequate leucocyte counts. Examples of the values obtained are the following.
CASE 1.—Total leucocytes counted, 500.
Polymorphonuclear leucocytes
.
.
.
60 per cent.
Large mononuclear
,,
. .
.
.
.
.
.
11.4 „
Small
,,
,,
. .
.
.
.
.
.
24
,,
Eosinophyl cells
.
.
.
.
.
.
.
.
1
, ,
Myelocytes.
.
.
.
.
.
.
.
.
1.2
,,
Transitional.
.
.
.
.
.
.
.
.
1 . 8
, ,
In termediat
.
.
.
.
.
.
.
.6 „
CASE 2.—Total leucocytes counted, 500.
Polymorphonuclear leucocytes
.
.
.
.
.
.
69.8 per cent.
Large mononuclear
,,
.
.
.
.
.
.
.
8.6
,,,
Small,,
,,
.
.
.
.
.
.
.
20.4 „
Eosinophyl cells
.
.
.
.
.
.
.
.
.4
,,
Myelocytes
. .
.
.
.
.
.
.
.
. 2
, ,
Transitional
.
.
.
.
.
.
.
.
. 6
, ,
Intermediate
.
.
.
.
.
.
.
.
0 . 0 , ,
CASE 3.—Leucocytes 250 per c. m. m. Total number counted 300.
Polymorphonuclear leucocytes
.
.
.
.
.
. 56 per cent.
Large mononuclear
,,
.
.
.
.
.
.
.
10.6
,,
Small
,, ,,
.
.
.
.
.
.
.
29.2 ,,
Eosinophyl cells
.
.
.
.
.
.
.
.
3.6
,,
Myelocytes
.
.
.
.
.
.
.
.
.
.6 „
CASE 4.—Leucocytes 437 per c. m. m. Total number counted 500.
Polymorphonuclear leucocytes
.
.
.
.
.
.
73 per cent.
Large mononuclear
,,
.
.
.
.
.
.
.
7
,,
Small
,, ,,
.
.
.
.
.
.
.
16
,,
. . Eosinophyl cells
.
.
.
.
.
.
.
.
4
,,
16
THE NATURE OF THE INFECTIVE PROCESS.—I have shewn that in
whatever position the bodies are found they are almost invariably contained in the
cytoplasm of cells. The large numbers of free forms seen in films of blood
obtained by splenic puncture can only be considered as forms artificially set free
from the cells they normally occupy. Two types only of cells have been so far
observed to harbour the parasite, i.e., the leucocytes and cells of endothelial nature.
It is above all the vascular endothelium which is involved in the type of infection
giving rise to splenomegaly. That the vascular endothelium plays an important
part in collecting the pigment of malaria is well known, but in the present case
there is the additional and most important fact that inclusion in the cytoplasm of
the cell is not prefaced or followed by the destruction of the parasite. We have
in so called malarial cachexia a condition characterised by the presence of
enormous numbers of the parasite in the viscera. At the same time the parasites
are with the greatest rarity to be found outside the endothelium or leucocytic
cytoplasm. From the inclusion of single bodies in the endothelium of certain
capillaries to the rupture of the large necrotic cells in the spleen and elsewhere,
the life of the parasite appears to be spent in the cytoplasm of an endothelium
cell. On the dissolution of the necrotic cells it would certainly appear that the
bodies are set free into the blood stream. Even then they must be again very
rapidly taken up again by cells, since it is acknowledged by all observers that
typical free forms in the peripheral circulation are excessively rare. The absence
of free forms in the blood of two cases where the parasite was readily found in
the leucocytes points to the same conclusion. It appears very probable that
inclusion in the cells of the body is not prejudicial to the life of the parasite, and
that it undergoes development by fission normally in the cells of its host.
Whether the great increase in the number of bodies in the endothelial cells is
mainly due to the phagocytic activity of the cell or to multiplication of the
parasite within its substance one hesitates to decide. The reduction of many
of the cells to mere bags containing multitudes of parasites certainly suggests
that active multiplication of included forms takes place.
With regard to the part played by the spleen and liver it is as yet premature
to form conclusions. On the whole it is probable that auto-infection of the
splenic and hepatic endothelium is constantly going on and forms the chief process
in the disease. The fact that bodies are found in the skin, intestine, lungs and
testis as well as in the large veins and in the lymphatic glands, draining certain
lesions, shews that wide dissemination of the parasite through the body also
occurs, and the function of the spleen and liver as storing organs must not be
overlooked.
It is of course possible that the endothelium infection is derived primarily
from very rare forms living in the red cells, but it seems, in the present state of
17
our knowledge, much more probable that the final disintegration of large necrotic
cells is the means by which fresh swarms of the bodies are set free to be taken
up again by the endothelial cells of the spleen and elsewhere.
A consideration of the main features of the process here exemplified, namely,
an endothelial infection, invites comparison with the processes in certain other
diseases.
DISEASES OF SEPTICÆMIC TYPE.—Infection by the new parasite as shewn
in so-called malarial cachexia has a strong resemblance to certain chronic septi-
cæmias, notably to some forms of malignant endocarditis.
That destruction of red cells is not necessarily due to actual invasion of the
corpuscle by the parasite is shewn in those cases of septicæmia where the
destruction of red cells is usually very great.
The finding of organisms in the circulating blood of cases of septicæmia and
pyæmia is also generally difficult and necessitates the use of considerable
quantities of blood, a point which has been elucidated especially by Kuhnan. 4
The experiments of Werigo 5 and others indeed shew that it is the endothelium
and leucocytes in the visceral capillaries which are mainly implicated when an
infection of the blood stream by micro-organisms takes place. We may indeed
almost consider this form of splenomegaly as a septicæmia in which the new
parasite is the infecting organism. We do not yet know how the parasite enters
the blood stream or whether it may give rise to conditions other than those found
in splenomegaly or in tropical ulcer, but in these we appear to have two very
distinct types of infection.
(1) A local lesion—Tropical ulcer.
(2) A septicæmia—the so-called malarial cachexia of India.
The fact that an infection may be mainly or entirely endothelial appears
to me to be important. The examination of the peripheral blood in Indian
cachexia is scarcely likely to have led to the discovery of the parasite. In
Malta fever splenic puncture is generally necessary in order to detect the infecting
micro-organism. Even in pronounced septicæmias, where cultural methods can
be employed, the detection of forms in the blood is uncertain, and a negative result
generally recognised as being without significance. By puncturing the spleen
one removes many endothelial cells and leucocytes which have remained in the
visceral capillaries, thus tapping an entirely different tissue from the blood. Such
a means of investigation should be a fruitful one in diseases where a blood infec-
tion appears probable, but where no organism is to be detected in the peripheral
blood, e.g., yellow fever.
DISEASES OF GRANULOMATOUS TYPE.—Tropical ulcer has many
features which would lead to its classification as a granulomatous lesion. Both
Cunningham and Wright shew that extensive deposits of granulation tissue are
D
18
formed in the dermis quite apart from ulceration which is evidently a secondary
process. That the organism under discussion is the cause of this deposit cannot
be doubted in the face of Wright's description. It is difficult to conceive of the
massing of a parasite of the red cell in such a position, and we most probably
have in tropical ulcer a granulomatous lesion in which the new parasite is the
exciting cause. It is premature to discuss the relation of the systemic infection
by the parasite to diseases of granulomatous type. Much depends upon
the relation of the disease to the small ulcers and papules described in this
paper.
The morphology of the parasite.
I have already drawn attention to the presence, noted by all observers, of
two chromatin masses in the bodies. I shewed that the arrangement of these
and the structure of the parasite in general is remarkably constant, and that a
schema of the parasite could be devised which would exhibit when viewed from
different directions most, if not all, the appearances shewn by the parasite in films.
The "tail" described by some authors as joining the large and small nucleus
I considered a strand or ridge of protoplasm left between two vacuoles. In a
proportion of the bodies, especially in the larger forms, I have since made out a
further detail of structure. This is a very distinct darkly-stained line, starting
from the neighbourhood of the small chromatin mass and ending as a rule abruptly
at a distance from the large mass. This line is nearly always at right angles
to the tail previously described, and by means of the schema it is possible to make
out that it lies in the line of division of the two hypothetical valves (Pl. II.
fig. 1).
In the first report I described the appearance in the bodies of a distinct
cuticle. Ross7 draws attention to the same appearance and the bodies as a rule
shew it to a marked degree. Instances of apparent rupture of this cuticle are
often seen (Pl. II fig. 2).
In some cases, especially when the tissues are taken post-mortem, the bodies
appear as protoplasmic masses only, and the appearance of a cuticle is absent.
The bodies also undoubtedly rapidly break up after the death of the host. There
appears some doubt then as to the resistant power of the apparent capsule, and
the appearance may be deceptive. As the bodies appeared not to be piroplasma,
and as from their number, their size and their morphology they appeared to
resemble somewhat the spores of microsporidia, I have made many attempts to
cause protrusion of the filament but without success. Blood from the spleen
containing the bodies was mixed with ether, strong and weak acids and ammonia.
Films were then made, thoroughly washed first in alcohol and then in water, and
stained by Romanowski's method. Films made from blood containing the bodies
19
were placed, without being allowed to dry, over the fumes of strong acids and the
vapour of ether. In most cases the bodies were to be readily made out, and, even
in the case of the strong acids, stained characteristically. No appearance of a
filament was detected.
The matrix. —Laveran, Ross, Manson and Low all describe a substance in
which many of the bodies are embedded. In films made from blood drawn from
the spleen during life this "matrix" is much in evidence. In films made post-
mortem it is not to be made out. The appearances are not quite the same in
every case and the matrix may be seen in one or other of the following forms.
(1) As irregular, fragmented and ragged masses. It may be a small and
very faint structure, often just visible, or it may be of considerable size. Large
masses of this nature, many times larger than a blood corpuscle, may often be
seen containing only a single body (Pl. II, figs. 3 and 4).
(2) As well-defined globular masses, smaller than, the same size as, or larger
than, a red corpuscle. The substance is as a rule finely reticular. It may be like
ground-glass in appearance. Identical bodies can be seen quite free from included
parasites, and budding from large cells of endothelial nature (Pl. II, fig. 5).
(3) Occasionally a faintly staining very hyaline substance, small in amount,
may be seen in which from 5 to 10 bodies are embedded. The bodies often lie in
vacuoles slightly larger than themselves. The amount of matrix in this case is
always very small, and it is never found projecting beyond the included bodies.
As regards the appearances described above, there can be no doubt that
(1) and (2) are the fragmented and budded cytoplasm of cells of endothelial
nature. The undoubted presence in some cases of pigment, either malarial or
derived from the skin and identical with pigment seen in the cells in sections,
definitely demonstrates their nature.
The third type, which is much rarer than the others, appears possibly to be
residual matter left over from the separation of the multiple division forms de-
scribed first by Laveran. In the first report I figured bodies having a clear
circular outline and containing three or more large, and an equal number of small,
chromatin masses, but in which no division into individual bodies could be made
out. In sections of the spleen I have been able occasionally to see such forms.
They contain as a rule about six large and six small masses. The large masses
are arranged peripherally and the small masses centrally. Such forms are en-
closed in the cytoplasm of cells as in the case of the bodies ordinarily seen.
Infection of other hosts than man. —I have not succeeded in producing
infection by inoculation of the bodies into animals. Monkeys and rabbits were
used, and blood containing the bodies was injected subcutaneously into the
peritoneum and into the blood stream (Intra-ventricular injection). Up to three
weeks after intravascular injection, and six weeks after injection into the tissues
D 2
20
and the peritoneum, no lesion had been produced and no bodies were found in
the spleens of the animals inoculated.
Comparison of the conditions found post-mortem in infection by
the new parasite, and in Trypanosome infection.
The organism used for comparison was a highly pathogenic trypanosome
which occurs naturally in the pariah dogs of Madras. This trypanosome
causes death in dogs in from 6 to 7 weeks after inoculation, and in rats in
from 8 to 10 days. The symptoms caused were emaciation, weakness, slight
œdema of the tissues about the eyes, a scurfy skin and distinct paresis of the hind
legs. In advanced stages of the disease the trypanosomes were abundant in the
peripheral blood.
In animals some hours dead, the trypanosomes were found in the large veins
in masses nearly as large as the field of the microscope. They shewed marked
changes. The general shape of the trypanosome was not in most cases recognis-
able. The large and small chromatin mass (nucleus and centrosome) were approxi-
mated, and in some cases shewed a remarkable resemblance to the chromatin
masses of the new parasite seen post-mortem. Numbers of filaments were every-
where to be seen. They, however, did not stain very deeply and in some clumps
were by no means conspicuous. Nothing like the definite outline of the new para-
site was ever seen and the resemblance was evidently superficial only.
The spleen in the case of three dogs killed on the point of death was some-
what, though not greatly, enlarged. Though the trypanosomes were abundant in
the peripheral blood, they were rare in the spleen both in the case of dogs and of
rats. It was difficult to find forms included in the spleen cells. When found, such
forms shewed two chromatin masses approximated so as to resemble those of
the new parasite, and as a rule no filament was seen. In some cases both the
filament and body were still to be recognised. In no case was the outline, so
characteristic of the new parasite, seen. The large crowded cells, seen in infection
with the latter, were absent. In none of the animals examined did there appear to
be a storing of forms in the spleen. Sections of the spleen shewed occasional
double chromatin masses in cell protoplasm, but the appearances were otherwise
quite unlike those seen in infection with the new parasite. The storing of enormous
numbers of the new parasite in an apparently unaltered state in the splenic cells
is one of the most remarkable features of infection by these bodies. In trypano-
some infection of the dog such a phenomenon does not appear to take place, and
from the paucity of included forms one is led to conclude that phagocytosis is not
great or that intracellular digestion is rapid.
In a dog strongly infected with piroplasma canis many of the leucocytes
21
contained included forms. Some of the forms shewed double chromatin masses
and had, as in the case of included trypanosomes, a slight resemblance to the new
parasite. In spite of many examinations nothing more than this superficial resem-
blance was encountered. Contrary to the state of affairs in the case of the new
parasite, intracellular digestion appeared to be in progress and many forms shewed
disorganised and scattered chromatin.
Conclusions.
1.The bodies described by Wright in tropical ulcer are indistinguishable
from those found in cases of enlarged spleen in Madras. In both cases
the bodies are for the most part included in the cytoplasm of cells of endothelial
nature. In tropical ulcer the bodies appear to be giving rise to a lesion of a dis-
tinctly granulomatous type.
2.In so-called malarial cachexia of India the bodies are very numerous in the
spleen, liver and bone-marrow. They are in considerable numbers, in some cases
at least, in the lungs and testes. In the kidney they do not appear to be in large
numbers. In the above named viscera they may occur in leucocytes, but for the
most part they are seen in cells of endothelial nature, especially in large cells
crowded with the bodies (macrophages).
3. Bodies may be present in large numbers in the granulation tissue associated
with ulceration of the large intestine in cases of so-called malarial cachexia.
4. Bodies may generally be found in small numbers in the granulation tissue
of small and larger ulcers, and in unulcerated papules in the skin of advanced
cases of so-called malarial cachexia. In this case, as in the testis, the bodies are
found for the most part lying singly in endothelial cells of the finest capillaries.
5.Bodies were found in a lymphatic gland which drained a skin lesion
containing the bodies. They were not found in a lymphatic gland draining only
normal skin.
6. Bodies may be found in leucocytes in the peripheral blood. I have not
seen unmistakeable forms in red cells either in peripheral or splenic blood.
7.The vast majority of the bodies lie in the cytoplasm of endothelium cells.
The cachexia is essentially an infection of the vascular endothelium and resembles
in many ways a chronic septicæmia.
8.The process of infection appears to be as follows. Bodies are taken up by,
or invade, endothelium cells in the visceral and certain other capillaries, e.g., gra-
nulation tissue. The endothelium cells increase in size and become more and more
distended with the parasites (macrophages). The cells finally undergo necrosis
and appear as mere bags filled with large numbers of the parasites. Eventually
such cells would appear to rupture and the contained bodies, which exhibit no
trace of intracellular digestion, are thus set free to be taken up again by cells.
Explanation of Plates.
PLATE I.
FIG. 1.—Adipose tissue infiltrated by granulation tissue. The figure shews several
bodies lying in the cytoplasm of cells. The section is from the edge of an ulcer. Case 5.
FIG. 2.—Young granulation tissue from the same ulcer.
FIG. 3.—Bodies lying in endothelium of a small vessel in the testis.
FIG. 4.—Body lying in cytoplasm of cell in the dermis. The section is from an un-
ulcerated papule.
FIG. 5.—Large cells crowded with the new parasite in the lymph nus of a lymphatic
gland. Case 5. Bodies are seen also in the stroma cells.
FIG. 6.—Large necrotic cell in same gland.
PLATE I.
Photogravure.
Survey of India 0ffices, Calcutta, May 1904.