W. L. Yakimoff and others 71 
curve was below the mean, only on the 8th day of infection rising to 16,851. 
On the day before death there was again a rise of the curve (to 14,254). 
Thus, v r e see that in mice the same phenomena are also observed as in 
dogs infected with trypanosomes, with the same three periods. 
First period. From the moment of infection till the appearance of try¬ 
panosomes in the blood, characterized by primary leucocytosis. 
During the second period leucopenia is observed. 
During the third period, preceding death, there is a secondary leucocytosis, 
but smaller than the primary. 
XII. PATHOLOGICAL ANATOMY 1 . 
The pathological changes in the animals that have succumbed as the 
result of experimental infection with the trypanosomes from camels are few. 
In mice the hypertrophy of the spleen is very striking. 
According to the data obtained by dissection of 96 mice, the spleen was 
greatly, sometimes enormously, enlarged in 66 (68*7 %); enlarged, not strongly, 
in 27 (28-1 %); and slightly enlarged in 3 (3-1 %). Regarding the changes in 
other organs a slight enlargement and hyperaemia of the liver was sometimes 
observed. 
In rats also the spleen is greatly enlarged. 
In guinea-pigs no marked hypertrophy of the spleen is observed. From 
the whole number examined in this respect the spleen was hypertrophied in 
25 %; slightly enlarged in 50 %; and not enlarged in 25 %. 
In rabbits the spleen is but slightly enlarged. 
The data concerning the dissections of the foal are as follows 2 : 
Slight emaciation. Under the skin on the neck and at the beginning of the breast, 
slight oedema of the connective tissue. On the right hind leg anteriorly to the heel articula¬ 
tion, a gelatinous oedema. In the 'peritoneal cavity about | litre of exudation of pink 
colour. In the stomach, numerous bot-fly larvae. In the duodenum, yellowish mucus, a 
great number of ascarids. Peyer’s patches not enlarged, but reticulate. The ileum, empty. 
The jejunum contains a greenish pulp; on the mucous membrane there is yellowish mucus. 
In the caecum, on the sub-mucous membrane, there are nodes of parasitic origin ( Strongylus 
armatus). Helminthic aneurism of art. coecalis. In the intermaxillary space and around the 
throat yellowish oedema. In the anterior part of the thoracic cavity there is a considerable in¬ 
filtration of ochraceous colour under the pleura. In the thoracic cavity itself there is about 
£ litre of fluid. The whole pericardial membrane is impregnated with a yellow, but denser, 
infiltration. On the transverse sulcus of the heart muscle there is a similar infiltration. In 
the right ventricle there are fresh clots of fibrin. The cardial valves are normal. The lungs 
are normal. The liver has a normal aspect; in section it is of a dark-brown colour. The 
kidneys are normal; the capsule is detached with difficulty. The spleen is normal. The 
oesophagus, trachea and pharynx are normal. 
Thus, the phenomena of trypanosomic character occurring in the foal 
were as follows: 
1 By W. L. Yakimoff. 
2 We are indebted to M. T. Romanovitsch for the dissection of the foal and pig. 
