336 
Journal of Agricultural Research 
Vol. XXVIII, No. 4 
dogs and that the administration of the drug after giving digestible fatty sub¬ 
stances such as cream increases the degree of intoxication. 
Fox No. 500 manifested lesions which were more or less characteristic of those 
observed in foxes dying from 1 to 5 days after treatment. The writers have else¬ 
where ( 6 ) called attention to the fact that although many foxes tolerate large 
doses or repeated treatment, a loss of approximately 4 per cent was suffered from 
what may be called a delayed intoxication. The doses which these foxes received 
ranged from 0.3 cc. to 0.54 cc. per kilo. In the majority of these fatalities the 
dose varied but slightly from 0.4 cc. per kilo. It should be mentioned, how¬ 
ever, that many foxes were dosed at the above range of rates and manifested no 
apparent unfavorable symptoms. Our experience has been that tolerance fo r 
carbon tetrachlorid varies not only in different foxes but in the same fox at dif¬ 
ferent times. 
Although pathological changes seemed to appear more constantly in the use of 
larger doses, the indications are that other factors than the dosage are involved 
in absorption of the drug. Some of these factors probably are: (a) Intestinal 
stasis, sometimes following treatment with the drug, as reported by Allen ( 1 ); 
(6) diseases, especially those associated with an acute enteritis; (c) character of 
the feed before and after treatment; and ( d ) idiosyncrasy of some foxes to the 
drug. 
Even though most adult foxes and pups over 3 months old will tolerate 
relatively large doses of the drug, it is probably advisable to make a practice of 
restricting the dosage to a range of 0.2 cc. to 0.3 cc. per kilo. Reasons for this 
are: (a) This range is usually attended with a relatively high anthelmintic effi¬ 
cacy against the more common intestinal worms of foxes; (6) the danger of 
s ystemic absorption of the drug probably tends to vary according to the amount 
of the drug used; and (c) reinfestation with hookworms and ascarids, especially 
the former, usually occurs within a few weeks, a factor frequently requiring a 
repetition of treatment. 
In conjunction with carbon tetrachlorid it is undoubtedly advisable to use a 
satisfactory purgative. The senior author has been conducting tests in which 
foxes were given a solution of Epsom salts by means of a stomach tube about 
two hours after the administration of the carbon tetrachlorid in soft elastic 
globules. Not giving the salts until two hours after such administration of the 
drug overcomes the possibility of the purgative leaving the stomach before the 
globules dissolve and release their contents. This method of treatment has 
been found effective in reducing losses from intoxication, but since it requires 
catching and dosing the foxes twice in connection with each treatment, a more 
practical method would be either to use soft elastic globules containing both 
carbon tetrachlorid and a satisfactory purgative or to administer carbon tetra¬ 
chlorid and a saturated solution of Epsom salts at the same time by means of a 
stomach tube. Recent papers by Lambert (7) in the treatment of human 
patients, and by Hall and Shillinger ( 5 ) in the treatment of dogs, indicate that 
carbon tetrachlorid is best administered with a saturated solution of Epsom salts 
given at the same time, the drug being safer and the efficacy equally high. 
CONCLUSIONS 
Carbon tetrachlorid in doses of 0.2 cc. or more per kilo was found very effective 
in the removal of hookworms and ascarids from foxes. At a dose rate of 0.25 
cc. or more per kilo, the drug was 100 per cent efficient against intestinal flukes. 
The drug proved about as effective in soft elastic globules as in hard gelatine 
capsules; that is, when feed and water were not given until three hours after the 
treatment. 
