170 
Journal of Agricultural Research 
Vol. XXIII, No. 5. 
bon tetrachlorid as an effective drug for hookworms. This bears out the 
supposition that it may prove feasible and safe to flood the digestive 
tract of dogs with sufficient carbon tetrachlorid to kill whipworms. A 
safety factor of -53 is a very high safety factor for drugs. According 
to Hall and Wigdor ( 21) the gastric capacity of the average dog is about 
1 liter or a little less. At a dose rate of 16 cc. per kilo, a dog of average 
weight (10 kilos) could take with safety 160 cc., or about one-sixth (16 
per cent) of its stomach capacity of carbon tetrachlorid. 
In a paper by Hall (13) it is noted that this drug is not of value in 
removing tapeworms of the genus Dipylidium , and probably will not 
be valuable in removing any tapeworms. 
We have carried on a few tests to determine the efficacy of carbon 
tetrachlorid when administered in soft capsules. Theoretically, the 
drug should be as effective when given in soft capsules as when given 
in hard capsules, but since some chemicals harden soft gelatine capsules 
and in time harden them to the point where they will pass the digestive 
tract unopened, it seems advisable to determine something definite in 
regard to the possible effects of carbon tetrachlorid on gelatine and the 
efficacy of the drug when administered in soft capsules. In the following 
tests the capsules used by us were from two lots, one less than 3 months 
old and the other over 4 months old but less than a year old, the date 
of manufacture not being definitely known to us. 
Dog No. 488.—Weight 13.5 pounds (approximately 6 kilos); given 
1.5-cc. soft capsule; no worms passed; post mortem, fourth day, 14 
hookworms, 46 whipworms, 31 Dipylidium caninum; efficacy, o per 
cent against hookworms, whipworms, and tapeworms. 
Dog No. 489.—Weight 19 pounds (approximately 9 kilos); given 
one 3-cc. soft capsule; first day, 16 ascarids, 1 whipworm; second day, 
7 whipworms; third day, 2 whipworms; post mortem, fourth day, 28 
whipworms, 2 Dipylidium caninum; efficacy 100 per cent against ascarids, 
26 per cent against whipworms, o per cent against tapeworms. 
Dog No. 491.—Weight 24 pounds (approximately 11 kilos); given 
one 3-cc. soft capsule; second day, 1 whipworm; fourth day, 2 hookworms, 
1 whipworm; post mortem, fourth day, 74 whipworms; efficacy, 100 
per cent against hookworms, 2.6 per cent against whipworms. 
Dog No. 492.—Weight 23 pounds (approximately 10.5 kilos) given 
one 3-cc. soft capsule; first day, 2 ascarids; post mortem, fourth day, 
10 whipworms; efficacy, 100 per cent against ascarids, o per cent against 
whipworms. 
In the foregoing tests the doses are approximately the therapeutic 
doses for the weights of the animals. The drug was 100 per cent 
effective against ascarids in the case of the two infested animals, 7 per 
cent effective against whipworms, and o per cent effective against tape¬ 
worms. It was 100 per cent effective against hookworms in the case 
of one dog and o per cent effective in the case of another. These findings 
must be considered in the light of the fact that all four dogs showed 
hookworm eggs on preliminary fecal examination. It appears, therefore, 
that there is some likelihood that all the feces passed were not collected 
by the attendant and that the other two dogs may have had all their 
hookworms removed by the treatment. Ignoring these doubtful cases, 
we may say that carbon tetrachlorid given in soft capsules in approxi¬ 
mately the therapeutic dose of 0.3 cc. per kilo may remove all the hook¬ 
worms present or may leave many or all of them. The dependability 
