i68 
Journal of Agricultural Research 
Vol. XXI, No. • 
dogs. It also shows a very high efficac}^ against ascarids. It removes 
whipworms when it enters the cecum, just as other anthelmintics do, 
but is substantially as uncertain in its action in single dose against this 
worm as are a number of other drugs. It is not of value in removing 
tapeworms of the genus Dipylidium and would probably be equally 
valueless against other tapeworms. It maintains its high efficacy 
against hookworms and ascarids when mixed with thymol at the rate 
of i mil of carbon tetrachlorid and io gr. of thymol, or when mixed with 
chenopodium in the proportion of carbon tetrachlorid, 3 parts, and 
chenopodium, 1 part, when given in capsules at a dose rate of 0.3 m. p. k. 
of these mixtures. The administration of the drugs in dosage less 
than 0.3 m. p. k. or without capsules is unsatisfactory. It should 
be noted in passing that in five of the cases noted where dogs were 
given from 0.1 to 0.3 m. p. k. of carbon tetrachlorid alone in cap¬ 
sules and no hookworms were found in the feces or post mortem, 
microscopic examination of the feces before treatment by the writer 
or by Messrs. Wigdor and Chapin of this laboratory had shown 
the presence of hookworm eggs. It is probable that in these cases the 
hookworms were removed by the drug but had not been found in the 
feces for one of two reasons. In the first place, in collecting feces from 
a cement floor 15 feet square, hookworms may be missed under certain 
conditions. In the second place, carbon tetrachlorid is one of the 
anthelmintics which frequently exert a destructive effect on the hook¬ 
worm, half of the worm, usually the anterior half, being distorted or 
missing in worms collected from the feces. Caius and Mhaskar (j) note 
that some anthelmintics (as thymol) have this effect and others (as 
chenopodium) do not. Carbon tetrachlorid is more destructive to dog 
hookworms than any drug the writer has used on them. 
RESULTS WITH OTHER ANTHELMINTICS 
To ascertain just how effective carbon tetrachlorid is against hook¬ 
worms in comparison with other drugs, the writer has summarized be¬ 
low the results published by him, alone or in collaboration with other 
workers, with other drugs against hookworms, noting other work of the 
same sort. 
CHLOROFORM 
Hall and Foster (9) found that chloroform in castor oil in dosage of 
0.2 m. p. k. administered to 5 dogs removed 474 hookworms and left 
356, an efficacy of 56 per cent. 
Hall (<?, pt. Ill) found that chloroform in dosage of 0.1 m. p. k. re¬ 
moved o hookworms from 1 dog and left 3, an efficacy of o per cent; in 
0.2 m. p. k. to 2 dogs it removed 13 hookworms and left 76, an efficacy of 
15 per cent; in 0.3 m. p. k. to 2 dogs it removed 3 hookworms and left 4, 
an efficacy of 43 per cent; in 2 in. p. k. it removed 1 hookworm and left o, 
