Apr. 26,1924 Carbon Tetrachlorid in the Treatment of Foxes 
335 
At 0.45 cc. per kilo. —In soft elastic globules given to two foxes, this dose re¬ 
moved 195 hookworms and left 1, an efficacy of 99.4 per cent; removed 1 ascarid 
and left none, an efficacy of 100 per cent; removed 2 immature Physaloptera and 
left none, probably an efficacy of 100 per cent. 
At 0.5 cc. per kilo. —In soft elastic globules given to two foxes, this dose re¬ 
moved 35 hookworms and left none, an efficacy of 100 per cent; removed 71 
ascarids and left 2, an efficacy of 97.2 per cent. 
At 0.6 cc. per kilo. —In hard gelatine capsules or soft elastic globules given 
to four foxes, this dose removed 19 hookworms and left none, an efficacy of 100 
per cept. 
In agreement with the findings of Hall (2) and Allen (I), these experiments 
indicate that administration of carbon tetrachlorid is attended with a relatively 
high degree of efficacy against hookworms and ascarids. They indicate also 
that this drug is effective against intestinal flukes and Physaloptera, but that it 
is ineffective against tapeworms. 
On the whole, the drug was found about as effective in soft elastic globules as 
in hard gelatine capsules. In the case of foxes No. 334. 356, and 357, feed and 
water were given about 1 % hours after treatment. It is very probable that 
the dose had not left the stomach and that the feed and water tended to 
dilute and mask the drug, thus reducing the efficacy of the treatment. 
Observations made later by the writers but reported in a previous paper ( 6) 
tended to indicate that feed and water probably should be withheld from foxes 
for about three hours after the administration of the drug in soft elastic globules, 
in order to allow sufficient time for the dose to escape from the globules and 
leave the stomach. 
In two instances (foxes No. 200 and 202) no worms were found either in the feces 
or on post-mortem, although a microscopic examination of the feces just before 
treatment had shown the presence of hookworm eggs. Hall (2) reported having 
had the same experience. The chances are that both animals were infested 
with hookworms and that the treatment was 100 per cent efficient in both cases. 
In another case (fox No. 730) two immature Physaloptera were passed and none 
was present on post-mortem. There is a possibility that this animal harbored 
more of these worms, which infest the stomach, but which were destroyed and 
digested to such an extent that they were unrecognizable when passed in the 
feces. According to Hall and Schillinger (4), worms infesting the stomach are 
liable to be destroyed by carbon tetrachlorid and digested instead of being 
voided in the feces. 
Of the 13 foxes which were given carbon tetrachlorid in hard gelatine capsules, 
one collapsed from inhalation of the drug, but under artificial respiration, re¬ 
covered. On the other hand, none of the 18 animals which were given the drug in 
soft elastic globules suffered inhalation-collapse. The writers {6) have found 
that in administering the drug cases of inhalation-collapse were not so likely 
to be encountered in the use of soft elastic globules as in the use of hard gelatine 
capsules. 
In the above experiments, four of the animals died, but carbon tetrachlorid 
apparently was responsible for the death of only three. Since both of the 
1-month-old pups died, the indications are that carbon tetrachlorid at a dose 
rate of 0.3 cc. per kilo is not tolerated by nursing pups. The constipation which 
occurred in these two animals undoubtedly resulted in increased absorption of 
the drug. Probably there were two other factors which predisposed them to 
intoxication, one being age susceptibility and the other the diet, which con¬ 
sisted of the milk of the vixen. The few analyses which have been made of the 
milk of fox vixens indicate that it is very rich in fat. Lamson et al. ( 8 ) found 
that dog puppies were more susceptible to carbon tetrachlorid than full grown 
