Oct. 10,1913 
Cysticercus Ovis 
43 
above, a considerable number of degenerated cysticerci were found in a 
sheep 83 days after infection, though most of the parasites were still 
alive and undegenerated. One other case is recalled in which degenerated 
and living cysticerci were associated. In this case the cysticerci in the 
heart, diaphragm, and muscles of mastication were degenerated and 
partially calcified, as were several found in various portions of the body 
musculature, but deep in the muscles of one hind leg there was a live 
cysticercus showing no signs of degeneration whatever. 
This accords with what would naturally be expected. One would 
expect live and degenerate cysticerci in the same carcass as the result, 
first, of variations in the longevity of cysticerci, as in the case of the 
experimental sheep mentioned above, or, second, as the result of infesta¬ 
tions occurring at different times. It seems that the latter must surely 
occur often. In view of the close association which commonly exists 
between sheep and dogs, the sheep in a flock attended by an infested 
dog are exposed to the chance of repeated infestation, and, hence, sheep 
must frequently harbor simultaneously cysticerci which have come from 
eggs ingested on various occasions. 
DIAGNOSIS OF SHEEP MEASLES 
So far as known, the presence of Cysticercus ovis can not ordinarily be 
determined in the living animal, and its diagnosis therefore depends upon 
a post-mortem examination. It is not always possible to determine 
definitely whether cysticerci found in sheep or goats are or are not C. ovis 
without resorting to the use of the microscope, but usually microscopic 
examination is not necessary. 
The location of Cysticercus ovis in muscle tissue differentiates it clearly 
from C. ienuicollis , which, so far as has yet been proved, is found only in 
relation with serous membranes. Cases occur, however, in which this 
rule can not be applied with certainty, as, for example, when the dia¬ 
phragm or abdominal muscles are involved it is sometimes practically 
impossible to state on the basis of location alone whether the parasite 
in question is C. ovis or C. ienuicollis —that is, the parasite may appear 
to be in direct relation both with the musculature and the serous mem¬ 
brane which covers the musculature. Here the size of the cysticercus 
may help to determine its identity; if over 10 mm. (two-fifths of an inch) 
in diameter, it is C. ienuicollis; if less than this size, it is probably C. ovis, 
but may be a young C. ienuicollis . 
The relation of the head to the caudal bladder—midway between the 
two ends in Cysticercus ovis (Pi. II, fig. 1) and at one end (Pi. II, fig. 5) 
in C. ienuicollis —will indicate the species if the parasite happens to be 
of a well-marked oval form. Even in very young cysticerci in which the 
head is yet rudimentary, the relative position of the head is the same as 
in the fully formed cysticercus. Cysticerci affecting the liver of sheep or 
