of this material should be poured into a glass dish and examined over 
a dark background, the dish itself being in a good light. The best 
background is that afforded by a shadowy floor when the dish is 
held at the level of the laboratory table. Parasites are visible as dis¬ 
tinct objects of definite outline, frequently white or yellowish, though 
sometimes red or motley colored, and usually actively motile. They 
may be picked out with a dissecting needle, forceps, or, if very small, 
with a pipette. Where such objects appear, but are not definitely 
recognizable, the use of a small hand lens, with a magnification of 6 
to 12 diameters, will usually aid in determining their nature. Failing 
this, one must resort to the use of the dissecting microscope, binocular 
or ordinary compound microscope. 
Examination of Stomach Contents of Large Animals 
With such large animals as horses, cattle and sheep, it is seldom 
necessary or feasible to wash and decant the stomach contents. The 
stomach of the horse may be slit and the gastric .mucosa carefully 
examined after the contents have been rolled out in such a way as to 
keep them together as much as possible. An examination of the ex¬ 
terior of this mass of contents, the part which has been in contact with 
the stomach wall, will usually show many more parasites than the 
interior of the mass, or the part which occupied the central portion 
of the gastric lumen. The rumen, reticulum and omasum may be 
slit and examined in a similar manner in the case of ruminants, but 
the fourth stomach or abomasum should be washed and decanted. 
Parasites are occasionally present in the first three stomachs. They 
are almost always present in the fourth stomach. 
The Intestines of a Horse Rarely Washed 
The small intestine of the horse is rarely washed and examined 
fcr parasites and the large intestine cannot be satisfactorily handled 
in this manner. In the latter, the examination of the intestinal wall 
and of the contents in contact with the wall indicate well the nature 
of the parasites present, and where it is desired to obtain all the 
parasites present, so far as possible, as is the case in testing anthel- 
7 
