472 
NATURE 
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[Sepz. 16, 1886 © 
Simultaneously with the above ‘experiments several inocula- 
tions with materials of the ulcer of cow No. IV. had been made 
into the skin of the groin of ten guinea-pigs and of three dogs. 
In the guinea-pigs no result was obtained ; but in one of the 
dogs one place of inoculation appeared swollen and inflamed on 
the third day. On the fifth day this place was an oblong ulcer 
of about a quarter of an inch in diameter ; the margin was red 
and swollen, but the centre was without crust (the animal had 
been frequently seen to lick it). On the seventh day the ulcer 
was much smaller, and it had nearly healed up by the tenth 
day. 
moe these experiments there can be no doubt whatever that 
by inoculating a particle of matter from the sores of an affected 
cow a positive result has been obtained in all four calves. In 
calf 3 this result was best and most striking. After an incuba- 
tion of about three days the places of inoculation became swollen, 
tender, and spreading ; on the fifth to the sixth day the change 
was distinct, the suceessful places having become sores ; in the 
marginal part showing vesiculation, and in the centre formation 
of crusts. The sore enlarged during the next few days, and on 
removing the crust a raw surface was exposed, the corium itself 
being found infiltrated. According to the intensity of the 
process the retrogressive change sets in later or sooner ; in slight 
cases the healing begins about the ninth or tenth day, in severe 
cases (calf 3) not before the end of the second week. 
Having thus demonstrated this disease of the cow to he 
directly communicable from animal to animal, I set to work (o 
study its minute anatomy. 
‘Lhe microscopic examination of fine sections through the ulcer 
of the cow shows the following conditions :— 
The corium throughout the whole extent of the ulcer is 
infiltrated with round cells. This infiltration, though densest in 
the central portions of the ulcer, is sufficiently pronounced eyen 
in the peripheral parts, but it gradually. fades away on passing 
from the ulcer to the normal skin. The infiltration in 
the deeper parts of the corium is limited to the vascular 
branches, but in the superficial parts is more diffuse, the 
papillz becoming at the same time thicker. This thickening of 
the papillae fades off towards the periphery of the ulcer. The 
most noteworthy changes are, however, present in the epithe- 
lium. In the p-ripheral portions of the diseased part there are 
present in the superficial layers of the stratum Malpighii close 
to the stratum lucidum, as also in the stratum lucidum itself, 
numerous cavities of different sizes. These cavities lie closely 
side by side ; the most superficial ones are either covered by the 
stratum lucidum or extend between the layers of this stratum. 
The former cavities descend into the depth of the epithelium ; 
at the very margin of the diseased part they are smallest, and 
they do not in depth comprise more than the superficial third of 
the stratum Malpighii, ‘They enlarge in depth gradually as we 
pass from the periphery of the ulcer towards its centre; at its 
very centre they involve the whole thickness of the stratum 
Malpighii. At the same time it is to be noticed that, at the 
marginal parts, the cavities, although closely placed side by 
side, are well separated from one another by thicker or thinner 
trabeculze composed of epithelium ; while at or near the centre 
the ulcer these trabeculae get destroyed, and the cavities become 
confluent, and the covering layers of the cuticle having here also 
given way, their contents extend on to the free surface of the 
ulcer. These contents, which go to form what has been above 
mentioned as the crust, spread thus gradually over the surface, 
not only of the centre, where the stratum lucidum has become 
lost, but also over the rest of the ulcer. In the marginal posi- 
tions, ze. where the superficial layers of the cuticle are still 
present as cover of the above cavities, this layer (/.e. the stratum 
lucidum) separates the contents of the cavities from the crust. 
The contents of these cavities consist (a) of an albuminous fluid 
looking, in hardened sections, uniformly granular or containing 
also fibrinous threads ; (6) of a few red b!ood corpuscles ; and 
(c) chiefly of round cells or pus cells, the nuclei of which, near 
to and on the surface, gradually break up into amorphous granu- 
lar matter. 
In the central parts of the ulcer the whole exudation undergoes 
degeneration into debris, and not only in its superficial, but also 
in its deeper portions. While some cavities contain very few 
cells and are filled chiefly with albuminous fluid (granular or 
fibrinous), others are almost entirely filled with pus cells closely 
packed together. In the papillze near the cavities the blood- 
vessels are engorged and there is also escape of red blood disks, 
On a careful examination it is evident that the origin of these 
cavities is in enlargement of and exudation into the tissue of the 
papillae, but only of those portions nearest to the stratum lucidum, 
and from hence arises formation of cavities in the cuticle. The 
whole anatomical details of the distribution and arrangement of 
these cavities recall vividly the conditions observed in the’vesicles 
of cow pock and of sheep pock, and on comparing under a low 
power of the microscope a section through a sheep pock witha 
the similarity is very striking indeed. 
There are, however, anatomical differences between the two 
diseases. The infiltration of the corium is slighter in the cow 
ulcer than in the sheep pock, and in the cow ulcer the cavities 
form in a more superficial stratum of the epidermis. 
There is in the disease we are now considering a good deal of 
infiltration of the epithelium by round cel!s derived from the 
cavities, not only into the stratum Malpighii, but also, and par- 
ticularly in the marginal parts, into the cuticle; the round cells 
burrowing in great numbers between the scales of this stratum, 
aud ultimately reaching the free surface to join those of the, 
crust. 
Fine sections made through the ulcer artificially induced by 
inoculation in the ear of calf 3, proved its complete identity in 
anatomical respects with the ulcer in the cow. The infiltration 
of the superficial corium ; the formation of cavities, filled with 
exudation cells and fluid, in the superficial layers of the epi- 
thelium, particularly between the layers of the cuticle; the final 
destruction in the centre of the ulcer of the covering cuticle ; 
and the extension of the exudation over the free surface to form 
here the crust, are the same in both instances. ‘ 
Microscopic examination of the internal organs of cow IV, 
revealed facts as follows :— 
In the lung.—Sections made through the portions above men- 
tioned as containing much congested lobules, show not only 
great congestion of the blood vessels, large and small, but a 
large amount of hemorrhage ; blood in substance being present 
in the air vesicles and infundibula, in the lymph spaces of the 
interlobular septa, and in the tissue and lymphatics of the pleura. 
In the latter membrane numerous diplococci are to be met with. 
Here and there the same diplococci occur in the alveolar wall 
and in the tissue of the interlobular septa. 
Sections through ¢%e diver show a great deal of change. Under 
the capsule, as well as in the substance of the liver, there occur, 
in connection with the interlobular branches of the portal vein, 
larger and smaller foci of inflammation, consisting in the presence 
of numerous round cells. Some of these foci are several milli- 
metres in diameter, others are very small. From the inter- 
lobular tissue the inflammation extends into the lobules between 
the liver cells. The liver cells of these lobules involved in the 
inflammatory process are swollen up, and many of them are 
undergoing disintegration. In sone of these foci, particularly 
these situated in the vicinity of the capsule, the round cells are 
so much crowded that given foci look almost like miliary ab- 
sce ses. The blood vessels are much distended and filled with 
blood. 
Numerous diplococci and short coccus chains occur in the 
parts surrounding the inflammatory foci. hese are particularly 
numerous near the capsule in the vicinity of inflamed parts. 
Sections through the 4/dzey showed well-marked glomerulo- 
nephritis ; infiltration of the sheath of the cortical arterioles with 
numerous round cells ; the epithelium of the convoluted tubules 
swollen, opaque, and in many places disintegrating. ; 
The lungs and kidney of cow III. showed on micr scopic 
examination the same appearance as in cow IV. ; in addition 
there was a good deal of round-cell infiltration in the wall of the 
infundibula and bronchi in the lung, and around the cortical 
arterioles in the kidney. In the blood-clots filling the alveoli 
and small bronchi of the lung there were present larger and — 
smaller clumps of micrococci. p 
Search was now made for micro-organisms inhabiting the 
tissues of the ulcer of the cow, with a view of ascertaining what 
were present, and afterwards whether any single kind of those 
found had the power, when dissociated from the diseased tissues 
and inoculated into healthy animals, of transferring the disease. 
Removing the crust, scraping off the most superficial layer, then 
squeezing the ulcer so as to collect a droplet of lymph, I spread 
it in thin films on cover-glasses, and dried, stained, and mounted 
the several specimens in the usual manner. Such a specimen, 
examined under the microscope, revealed a number of red blood 
disks, mixed up with large numbers of pus cells, each of which 
contained two, three, or four small nuclei and remnants of epi- 
: 
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section through the ulcer of the cow now unier eg 
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