34 BULLETIN 125, TJ. S. DEPARTMENT OF AGRICULTURE. 
In the two cases of forced, feeding of seeds in 1914 the average toxic 
dose was 0.153 pound; inasmuch as the animal receiving the maxi- 
mum amount was very sick, the actual toxic limit must be consid- 
ered to be close to the minimum figure of 0.11 pound. It will be 
noticed that the cases of feeding of seeds in 1913 had practically the 
same average dose as the cases of forced feeding in 1914; this is 
accounted for by the fact that these animals ate the seed in such a 
short time that the results were similar to those from forced feeding. 
It is interesting to note in Table III that the lethal dose is only 
slightly larger than the toxic dose. 
In transferring these results to the probable dosage when sheep 
are range fed, the feeding habits of the sheep must be taken into 
consideration. In the corrals the sheep do not, as a rule, eat as 
readily as when on the range. When the sheep in a band are grazing 
together, both imitation and jealousy affect the quantity of any plant 
which a sheep eats in a given time; so it is reasonable to suppose 
that if feed is short and Zygadenus fairly abundant, sheep may eat 
much more in a short time than they would under corral conditions. 
Under such circumstances, the dosage might approximate that of 
the drenching experiments. Therefore, it appears probable that 
animals feeding on the range might, because of the more rapid eating, 
be poisoned with much less than when in corrals. 
EXPERIMENTS WITH HORSES AND CATTLE. 
Three experiments were made of feeding Zygadenus to a horse, 
as shown in Table I (section D), Z. venenosus being used in two tests 
and Z. elegans in one. The smallest quantity fed in these experi- 
ments was 12.1 pounds per 1,000 pounds of weight, and the largest 
was 15 pounds. In each instance the feeding was extended through 
several days, and the feeding of 15 pounds extended through 6 days. 
If the quantity necessary to poison a horse should be in the same 
proportion to its weight as that required to poison a sheep, it would 
be, according to our dosage, at least between 11 and 12 pounds, and 
probably much more. It may be presumed, therefore, that in these 
cases the amount fed was not sufficient to produce toxic effects. 
There is, however, abundance of evidence that horses are poisoned 
by Zygadenus, although not ordinarily with fatal results. 
Section C of Table I shows the results of feeding Zygadenus 
venenosus to three cattle. Two of these animals, both of which 
received leaves and flowers, showed symptoms of poisoning, one 
on 58 pounds per 1,000 pounds of weight and the other on 46. 5 
pounds per 1,000 pounds of weight. In these cattle, therefore, 
the average toxic dose was 52.25 pounds, which was fed in an average 
of 6+ days. This compares fairly well with the results reached with 
