Gr. H. F. JNTuttall, H. B. Fantham and A. Porter 339 
emulsion of infected spleen and bone marrow subcutaneously into a 
fresh animal. The result was negative 1 . The experiment was also 
dictated by the belief that the invasion of the corpuscles may take place 
in the spleen or bone marrow and that the corpuscles act chiefly as 
vehicles (after the manner of an omnibus) for parasites destined solely 
to gain an entry into ticks for the purpose of undergoing further 
development. On the “omnibus hypothesis” the corpuscles are 
penetrated by parasites as the blood circulates through the internal 
organs ; the parasites multiply in these organs but not in the corpuscles. 
As the disease progresses more and more protozoal passengers board 
the transporting vehicles, the corpuscles. This hypothesis offers an 
explanation of the fact that (1) the disease is not communicable by blood 
inoculation; (2) that the percentage of infected corpuscles not only 
increases steadily, but that the percentage of corpuscles containing 
many parasites grows as the disease advances; (3) that the parasites do 
not persist in the blood after recovery. It is, of course, conceivable that 
intracorpuscular multiplication may take place ; if it occurs the process 
must be very slow. 
The assumption appears justified that the parasites obtain nutriment 
from the corpuscles they inhabit. The discovery recently made by 
Meyer that East Coast Fever may be communicated by transplantation 
of the affected spleen or pieces of that organ goes to support the 
hypothesis here advanced, for doubtless the transplanted splenic tissue 
lived on for a time in the peritoneal cavity of the experimental animals 
and served as a nidus wherein the parasites continued to multiply. 
Meyer’s experiments demonstrate that the spleen, and possibly other 
internal organs, serve as the primary seats of the invasion of the blood 
corpuscles by the parasites. 
Summarizing our observations on the living parasite, we would state 
that they show active movements within the corpuscles and at times 
undergo alterations of form. No structural details can be made out 
in living parasites. We have not obtained any conclusive evidence 
that the parasites multiply within the infected corpuscles, but at 
times appearances were observed suggesting this possibility. In several 
1 Koch and his colleagues have recorded similar results following the inoculations of 
pulped spleen and lymphatic glands. Mr S. Stockman, M.R.C.Y.S., informs us that he 
and Mr A. Theiler, working in the Transvaal, likewise obtained negative results from 
inoculations with spleen emulsions. Meyer (ix. 1909, Hague Congress of Veterinary 
Medicine) has recently succeeded, however, in communicating the disease by transplanting 
the whole spleen or portions of infected spleen into the peritoneal cavity of healthy 
animals. 
