Journal of Agricultural Research 
Voll. XXIII, No. 3 
I 7 8 
between 1.66 and 3 cc. per kilo. Since the therapeutic dose rate is 0.6 cc. 
per kilo, the margin of safety is between 2.66 and 5, a very small margin 
for swine as compared with the large margin in the case of carnivores, 
poultry, and some other animals. Swine are therefore rather poor 
subjects for treatment with carbon tetrachlorid or other drugs acting 
on the liver—a fact probably associated, among other things, with the 
prevalence of parasitic hepatic cirrhosis in swine. That carbon tetra¬ 
chlorid might prove unsatisfactory for swine on actual test was pointed 
out in an article by Hall ( 14 ). 
TEST ON HORSES 
In a paper by Hall (15) tests of carbon tetrachlorid for removing bots 
and worms from horses have been reported. Two animals were given 
carbon tetrachlorid alone in doses of 25 and 50 cc. The smaller dose 
removed 23 per cent of the Gastrophilus intestinalis from the stomach 
and 29 per cent of the G. veterinus (G. nasalis) from the duodenum, or 
24 per cent of all bots present. The larger dose removed 23 per cent of 
the bots from the stomach and iop per cent of the bots in the duodenum, 
or 25 per cent of all bots present. Since the smaller dose is equivalent 
to the therapeutic dose of carbon bisulphid (CS 2 ) which will remove all 
the bots present, carbon tetrachlorid is evidently inferior to carbon 
bisulphid as a remedy for bots, although the efficacy shown by carbon 
tetrachlorid is superior to that of anything that has been used, except 
carbon bisulphid, no other drug having shown even the 24 to 25 per 
cent efficacy shown by carbon tetrachlorid. 
A number of stomach worms (Habronema sp.) were found post mortem 
in the stomach of one horse, none having been found in the manure. In 
our opinion, this can be taken only to prove that carbon tetrachlorid 
and other potent drugs will not kill these worms when they are buried 
in the mucosa. It appears entirely probable that carbon tetrachlorid, 
carbon bisulphid, or chenopodium will kill those individuals with which 
they come in contact. It further appears that as a rule the appearance 
of the dead worms in the manure is not to be expected. A dead worm 
in the stomach is in effect a very small amount of protein material in an 
environment where protein digestion is being carried on, and it is to be 
expected that the worm will be wholly or in large part digested before it can 
leave the stomach unless it is killed near the pylorus and is very promptly 
carried out by peristalsis. Such fragments of Habronema as might 
escape in this manner would almost certainly be completely digested 
and disintegrated in their passage through the small and large intestines. 
The journey through the large intestine of the horse may require days 
and even weeks for individual objects, and Hall, Smead, and .Wolf ( 20) 
found dead bots in the large intestine as late as 17 days after the admin¬ 
istration of carbon bisulphid. Confirmatory evidence in regard to the 
digestion of dead worms in the stomach will be given later in connection 
with our studies on treatment for stomach worms in sheep. It therefore 
appears that the technic used here is not adapted to obtaining accurate 
information in regard to the efficacy of anthelmintics on worms in the 
stomach and that the findings in regard to treatments for these worms 
must be reviewed with reference to the occurrence of gastric digestion of 
the worms. 
