525 
of the parasites from the peripheral circulation occurred between 
2 and 5-30 a.m. 
In the present case, material at this period was obtained with less difficulty. 
A rat (1,540 Bl inoculated on July 20, 1907, showed very numerous parasites in 
thick films of tail-blood on the morning of July ^5. It was examined five hours 
later, when the parasites were found to have disappeared almost entirely from the 
peripheral circulation ; the animal was then killed for the purpose of examining 
the organs at the stage of crisis. 
Very few spirochaetes were observed in the vessels and capillaries 
of lung and kidney. The spleen showed a moderate number of laigc 
phagocytes containing partly digested and fragmented spirochaetes. 
In the liver, on the contrary, the capillaries were crowded with 
parasites, or, to be more exact, were nearly or quite occluded by 
swollen mononuclear phagocytes — endothelial cells and cells of 
Kupfer—filled with innumerable black granules, many coiled forms 
and only a few normal spirochaetes. 
This observation seems to lend additional support to t e 
hypothesis that the coiled forms are due to the influence o 
phagocytosis. At the height of the infection the vessels o t e 
different organs were crowded with free, apparently unaltered spiro 
chaetes, and the liver showed in addition a great num er 0 
intracellular coiled forms ; at the crisis the extracellular parasites ha 
disappeared almost entirely, and in the liver were found, besi es t ® 
cell-included coiled forms, large numbers of fragmented parasites a 
granules, evidently products of intracellular digestion. 
The occlusion of many of the capillaries of the liver by swollen 
phagocytes seems to account for the hemorrhagic an 1 
infarcts observed by Breinl and Kinghorn. Levadit. is als ° . 
to explain the changes observed by him in the liver o in ec e 
by obstruction of the blood-vessels of this organ. 
bibliography 
Levaditi et Mancunian. Recherches sur Infection * 
spirillede la 1 Tick-fever.’• Annales de 1 InSt „ 1 , a>t ’ f IC ’the Parasite of the 
Beeinl and Kinghorn. ' r^xxforr Lverpoo! 
African Tick-fever (Sfirochneta duttoni). 
School of Tropical Medicine, September, I 9° 6 - T'ntersuchungen 
v. Prowazek. Morphologische und XXIII, 
fiber Huhnerspirochaeten Arbeit, a. • a 
1906. S. 554. 
