182 
Journal of Agricultural Research 
Vol. XXIII, No. 3 
genera Nematodirus , Cooperia , Ostertagia , and Trichostrongylus. This is 
a surprisingly good result, since these small worms have been resistant 
to the drugs heretofore tested on sheep. In the case of these worms 
and other small worms, the principle has been laid down and accepted 
by parasitologists that small worms are more difficult to remove than 
large ones. Certainly it has required more time and investigation to 
find any treatment whatever for their removal. That carbon tetra- 
chlorid will fail to remove a large percentage of these worms at times 
was shown in our second series of 2 sheep, in which the drug removed 
27 per cent of the trichostrongyles present in one animal and removed 
only about 3 per cent of 1,100 trichostrongyles present in the other 
animal. In this case the worms left were mostly Cooperia, Ostertagia, 
and Trichostrongylus, the drug being apparently most effective against 
the Nematodirus present. This is of interest, since Nematodirus is 
apparently a bloodsucker and is apparently a more injurious parasite 
in the case of sheep than any of the other trichostrongyles named. In 
the third series doses of 4 and 12 cc. apparently failed to remove any of 
the 121 trichostrongyles present. 
Carbon tetrachlorid was of no value in removing tapeworms from 
sheep, removing only 1 and leaving large numbers. One sheep had 1,149 
specimens of Moniezia post mortem. This agrees with the findings 
in the case of dog and chicken tapeworms. 
The two lambs used in our second experiment were selected as the 
weakest and most unthrifty of a lot of lambs. The one which was given 
30 cc. of carbon tetrachlorid weighed only about 33 pounds (15 kilos) 
and was down and apparently dying the day we killed these two lambs. 
Whether the carbon tetrachlorid contributed anything to the bad condi¬ 
tion of the animal on this day is problematical. However, it is commonly 
true that very sick or weak animals are intolerant of anthelmintic treat¬ 
ment, and it is possible that the drug may have injured this one. Such 
animals are practically worthless and if they die after treatment, little 
or nothing is lost. Since most of the sheep used in the tests were off 
feed for a time following treatment, it appears that the safety factor of 
this drug for sheep is not very large. In this connection it may be 
recalled that Hall and Foster (19) found sheep intolerant of chloroform, 
one animal dying after a dose of 5 cc. The nature of the ruminant 
stomach probably favors rapid absorption of volatile drugs. 
TESTS ON CATTLE 
The following tests on cattle were conducted: 
Heifer No. 1009.—Weight, approximately 250 pounds (approximately 
114 kilos); dose, 100 cc. of carbon tetrachlorid in 350 cc. of castor oil, 
after fasting 36 hours. Passed 399 stomach worms (Haemonchus con- 
tortus) during first 2 days, 396 hookworms ( Bunostomum phlebotomum) 
during first 6 days, 234 nodular worms (. Proteracrum radiatwn) during 
first 6 days, and 4 whipworms ( Trichuris ovis) during first 3 days; post 
mortem, on sixth day, 426 hookworms and 1 tapeworm {Moniezia sp.). 
Heifer No. 1002.—Weight, approximately 175 pounds (approximately 
80 kilos); dose, 100 cc. of carbon tetrachlorid in hard capsules, after 
fasting 36 hours. Passed 8 stomach worms and 8 nodular worms in 
first 2 days, and 453 hookworms in first 4 days; post mortem, on fourth 
day, 4 hookworms in the small intestine and 2 hookworms in the cecum. 
