Oct. xo, 2913 
Cysticercus Ovis 
5 1 
March 28, were still alive on March 31. After its arrival in Washington 
the meat was kept in an ice box, at a temperature not lower than 40° F. 
As to the period of survival when frozen it was found in one experiment 
that the cysticerci in a sheep slaughtered on October 15, 1912, were 
dead on November 7, 23 days after slaughter, the mutton meanwhile 
having been kept in a frozen condition. Through an oversight no exami¬ 
nation of the mutton was made at intervening dates, so that no informa¬ 
tion was obtained as to how long the parasites actually retained their 
vitality. The cysticerci were observed by Dr. L. E. Day, who took 
charge of this experiment on November 7, to be slightly shriveled after 
thawing. On November 7, about half a pound of the infested mutton 
was fed to a dog and similar amounts on November 8, 9, 10, and 11. On 
the last date another dog was also fed. Autopsy on the former dog on 
December 2, 24 days after feeding, showed no parasites of any kind in 
the alimentary tract. The other dog when examined post-mortem on 
January 4, 53 days after feeding, showed a few Dipylidium caninum , 
but no other parasites. 
From this experiment it appears probable that a period of three weeks 
is sufficient, as in the case of Cysticercus bovis , to insure the death of 
cysticerci in mutton. Since, however, Cysticercus ovis is not transmissible 
to man, the same necessity of holding slightly affected carcasses in cold 
storage for a sufficient period of time to destroy the vitality of any 
cysticerci which may have been overlooked does not exist. In this 
respect it is accordingly not so important as in the case of Cysticercus 
bovis to know how long the cysticerci may survive after the slaughter of 
its host. 
PROPHYLAXIS 
In addition to the highly important preventive measure of destroying 
the carcasses of all dead sheep by burning, the simplest, most feasible, 
and most effective means of eradication is to keep the dogs of the ranch 
or farm free from tapeworms by systematic medicinal treatment. As 
the sheep-measle tapeworm in dogs begins to produce eggs about two 
months after infection, judging from the results obtained in the experi¬ 
ments, it is evident that dogs should be treated about every two months 
in order to remove any tapeworms acquired since the preceding treat¬ 
ment before they have developed sufficiently to produce eggs. In prac¬ 
tice, however, such frequent treatment seems scarcely necessary, and it 
is fairly certain that effective control of tapeworm infestation can be 
maintained if dogs are submitted to treatment four times a year—that 
is, every three months. The following method of treatment is employed 
by Dr. E. T. Davison at the Federal Quarantine Station at Athenia, 
N. J., and has proved very satisfactory in the case of imported sheep 
dogs quarantined and treated on account of tapeworm infestation: 
Allow the dog to have the usual feed and drink about 3 or 4 p. m. on the day 
preceding treatment, but give nothing further in the form of food or drink, with 
