456 INFECTIOUS ANEMIA IN HORSES 
mentions several bacteria which he 
isolated from the cases in Dakota. 
Udall and Fitch found B. coli present 
in the organs of the animals dead of 
this disease. Carré and Vallée passed 
the blood serum of an infected ani- 
mal through a Pasteur filter and pro- 
duced the disease by the injection of 
the filtrate into solipeds. This deter- 
mined its filterable nature. Francis 
and Marsteller produced it by the 
injection of filtrates of blood. This 
experiment supports the theory that 
the disease in Europe is the same as 
that occurring in this country. 
The virus is present in the urine as 
well as in the blood. Carré and Vallée 
found that it was destroyed by heat- 
ing at 58° C. for one hour. Drying 
at room temperature does not alter its 
virulence. It was only after seven 
months’ drying that the virus was 
rendered inert. It resists putrefac- 
tion for a long time. Van Es states 
that in natural conditions the virus 
is able to withstand the climatic in- 
fluences of our severe northern win- 
ters. 
The Seyderhelms’ and the Japanese 
Commission found that the disease 
is produced by the larvee of bot-flies 
(Gastrus larva) which occur in large 
numbers in the stomach and intestines 
’ of infected horses. They claim to have 
produced the disease by the injection 
of an extract prepared from these 
larve. The Japanese Commission, 
as a result of their experiments, dis- 
Fic. 106. PHOTOGRAPH OF LONGITU- miss “bots” as having nothing to do 
DINAL SECTION OF FEMUR OF HORSE With the disease. They believe, how- 
iit Udall and Pitch). Ne MA ever, that the biting horse flies (chry- 
