Jan- 20, 1923 
Carbon Tetrachlorid as an Anthelmintic 
169 
it comes in contact. If the anthelmintic passes from the ileocecal valve 
down the colon, it will not come in contact with the whipworms in the 
cecum, and except in very heavy infestations the whipworms present are 
usually found clustered near the tip of the cecum. In the experiments 
on dogs it was reported that when carbon tetrachlorid was administered 
in capsules at a dose rate of 0.1 or 0.2 cc. per kilo it removed no whip¬ 
worms, at a dose rate of 0.3 cc per kilo it removed less than 10 per cent 
of the whipworms, and at a dose rate of 1 cc. per kilo it removed 100 per 
cent of the whipworms present in one dog. These results suggest that the 
problem of removing whipworms by insuring the entrance of the drug 
into the cecum might be solved in either of two ways. One of them is 
to give repeated small doses of some anthelmintic which is not a gastro¬ 
intestinal irritant, such as santonin, over a period of a number of days 
in order that the entry of the drug into the cecum be insured by in¬ 
creasing the number of its chances to enter the cecum. This is a method 
which has been tested and proposed by Hall (9, 12). Another solution 
of the problem would be to employ a drug which could be used in such 
large quantities that its entrance into the cecum would be insured be¬ 
cause of the large quantity used. Carbon tetrachlorid might be such a 
drug, though this remains to be proved. However, it will be noted that 
as the dose rate for this drug was raised, the efficacy increased from 
o to 100 per cent, the latter result being attained with a dose of 1 cc. per 
kilo. Tests of toxicity were reported by Hall (12), showing that dogs 
would survive a dose of 1.5 cc. per kilo without showing symptoms of 
injury or any evident lesions post mortem 
We have carried on additional toxicity tests of this drug on dogs as 
follows: Three dogs (No. 436, 425, and 426) weighing, respectively, 
20.5 pounds (about 9 kilos), 21.5 pounds (about 10 kilos), and 39.5 
pounds (about 18 kilos) were each given 10 cc. of carbon tetrachlorid 
in capsules. Seven days later they were given, respectively, 30, 50, 
and 60 cc. of this drug by catheter to the stomach, a dose rate of 3.33 
to 5 cc. per kilo. Thirty-nine days later the first two of these dogs 
(No. 436 and 425) were given, respectively, 91 to 60 cc. by catheter to 
the stomach. At this time dog No. 436 weighed 13 kilos, the dose rate 
being 7 cc. per kilo. One week later, dog No. 425, previously given 
60 cc. of carbon tetrachlorid, was given 156 cc., or 12 cc. per kilo; and 
another dog, No. 424, weighing 20 kilos, was given 240 cc., or 12 cc. 
per kilo. A little less than two months later, dog No. 424 was given 
320 cc., or 16 cc. per kilo. These animals showed no bad effects imme¬ 
diately after treatment or subsequently. Since no bad effects were 
observed, the highest dose rate, 16 cc. per kilo, gives a safety factor of 
over 53 for the therapeutic dose of 0.3 cc. per kilo. The two doses being 
considered, dog No. 424 received in less than two months 560 cc., or 
28 cc. per kilo, or more than 93 times the therapeutic dose. At a single 
dose this dog received over 53 times the therapeutic dose. These figures 
indicate that carbon tetrachlorid is uncommonly safe. The therapeutic 
dose of oil of chenopodium for the removal of all ascarids present is 
0.1 cc. per kilo. The minimum lethal dose is 0.5 cc. per kilo. This 
gives a safety factor of 5. So far we have failed to find the minimum 
lethal dose rate for carbon tetrachlorid, since our dogs have survived 
what we regarded as dangerously high doses; but the present ascertained 
safety factor is over 53, or more than ten times as great as that of oil of 
chenopodium as an effective drug for ascarids compared with that of car- 
