general EaTEology 0E u surra” in animals. 59i 
the disease, but as we have endeavored to show, there 
is much to learn about this parasite and its behavior’in the 
body of the animal. Our means of investigation are gener¬ 
ally so limited and imperfect that in any inquiry we must 
note everything that might lead us to form anything like an 
accurate notion of the facts presented. Much valuable data 
has been advanced by the different writers in support of their 
beliefs; still, all is hypothetical, and the need for extended 
inquiry into the pathology of surra was never better shown. 
In fact, we are not far from the truth in asserting that a wider 
knowledge of the laws of pathology may be requisite before 
the problem can be properly approached. 
After all, the main problem is, what disease in mankind is 
suira allied to in its main points? Has it any identity to any 
disease of human beings? To what disease does it bear the 
gieatest resemblance? And in what points? So far the an¬ 
swers to these questions have not been faced properly; for 
although the answer to them would greatly assist our inquiry 
into the pathology of the disease, yet hitherto it has been 
found impracticable. 
The general name of ague, intermittent fever, or malaria 
is given to a disease produced by a common cause;* and the 
same cause is credited with producing other more severe 
foi ms of disease called remittent fever, pernicious anasmia, 
malarial cachexia, etc. It may be a question whether all these 
forms of fever aie due to the same cause; but the general 
opinion is that they all constitute the same disease in various 
degrees of severity. 1 he one feature common to all is fever 
which remits and leturns periodically. The other symptoms 
need not be considered here. It will suffice, perhaps, if we 
take up the characters of surra first. We shall then be able 
to arrive at an opinion as to which condition it is allied to in 
* With regard to the nature of the germ, certain researches seem to identify 
it with a certain bacillus found in the soil of malarious districts ; but more re¬ 
cently an animal organism, a flagellate infusorian, has been found in the blood 
of ague patients, which seems more probably the cause of the disease. It has 
been shown by Marchiafava and Celli that the inoculation of the blood of an 
ague patient into healthy persons will reproduce the disease in them. 
