Oct. ro, 1913 
Cysticercus Ovis 
41 
A carcass examined by Dr. 0 . B. Hess at Seattle, Wash., not recorded 
above, showed 1 cyst in the heart, 3 in the masseter muscles, 15 in the 
forequarters, 22 in the “rack/' 13 in the saddle, and 7 in one hind leg. 
The number in the diaphragm or visible superficially was not stated. 
Besides the carcasses referred to above there were examined in Chicago 
in April, 1912, by Dr. W. C. Siegmund and the writer, 59 carcasses which 
had been retained in the course of routine inspection on account of the 
presence of cyst in the heart. The examination consisted in examining 
carefully the diaphragm and the surface of other exposed muscles, 
examining the internal and external muscles of mastication and tongue 
after slicing them, and finally examining the cut surfaces after the carcass 
had been cut into three to five market cuts. 
Four carcasses for which the number of cysts in the heart was not 
recorded showed no additional cysts. Fifty carcasses had one cyst in 
the heart. Ten of these had additional cysts, three having one cyst 
each in the diaphragm, two having one and two cysts, respectively, in 
the muscles of mastication, two having one superficial cyst each in the 
abdominal musculature and on the hind leg just below the patella, 
respectively, three having one cyst each on the cut surface of a hind 
quarter, “rack,” and forequarter, respectively, and one having a cyst 
in the wall of the esophagus. Three carcasses which had two cysts in the 
heart showed no additional cysts. Two carcasses which had three cysts 
in the heart showed no additional cysts. 
DEGENERATION OF CYSTICERCUS OVIS 
The cysticerci observed in the course of the routine post-mortem 
inspection of sheep are usually more or less degenerated, and are either 
in a condition of caseation or calcification (Pis. Ill, fig. E , and IV, fig. 1). 
This does not necessarily indicate that live cysticerci are relatively rare. 
It may be accounted for in part by the fact that degenerate cysticerci 
are much more conspicuous than the live parasites and, hence, less 
likely to be overlooked. On the other hand, the validity of this explana¬ 
tion is somewhat offset by the possibility that the cysticerci remain alive 
only for a short period compared with the length of time they persist in 
the degenerated condition, in which event one would expect to find 
degenerated cysticerci more often than living ones. How soon degenera¬ 
tion may begin or how rapidly it may proceed is uncertain, but it is 
quite clear that in different instances the process varies considerably in 
these respects and in its character as well. Degeneration as noted else¬ 
where may occur before the cysticerci have reached their full develop¬ 
ment. It is probably often influenced by the presence of bacteria 
introduced by the parasite itself or carried to the cyst by the blood 
stream, and bacterial action may perhaps have a great deal to do with 
the large size commonly attained by the degenerate cysts of Cysticercus 
ovis. 
