208 
ALBERT HASSELL. 
are sufficiently recuperated for another assault. In other 
words, as has been more tersely and less grandiloquently 
stated, the bacteria light the fire which ultimately consumes 
them. Thus is the vis medatrix natures again exemplified. 
On the other hand, the condition of the body may determine, 
to some extent, the existence of fever. For it is said that cri¬ 
sis or lysis in fevers occurs either because the cause of the 
fever has been destroyed, or because the heat centres have 
become exhausted. In the latter instance fever is re-established 
with the recuperation of the calorifacient centres. 
But is it not a reasonable proposition, that while fever 
may be a remedial agency in its way, yet like any other 
potent measure, it must be controlled and kept within bounds, 
as in using a drug of great efficacy we must regulate the 
amount administered, else what may be its power for good 
become transformed into an instrument for evil. 
A NEW SPECIES OF TREMATODE INFESTING CATTLE. 
By Dr. Albert Hassell, Veterinarian, Baltimore, Md. 
In the collection of the Bureau of Animal Industry is a 
bottle containing specimens of a trematode new to science, of 
which I give the following character: Fasciola carnosa (nov. 
sp.) 
Body flat, elliptical in outline, very thick, 
margins straight; mouth terminal, lip circu¬ 
lar with triangular orifice; acetabulum 
small, circular, with triangular aperture; 
genital pore small, situated midway be¬ 
tween the mouth and acetabulum. Length, 
45 millimetres ; breadth, ?2 millimetres at 
widest part; habitat, liver and lungs of ox. 
In general appearance this parasite differs 
from the fasciola hepatica (Linn) and fasci¬ 
ola gigantea (Cobbold) in many characteris¬ 
tics. In point of size it is intermediate be¬ 
tween the two, having an average length of about 45 millimetres. 
In outline it differs from either by having no defined head 
Fasciola carnosa. (Has¬ 
sell), from liver of a Colo¬ 
rado steer—natural size. 
