LARKSPTIK POISONING OF LIVE STOCK. 
71 
results : No. 637 was poisoned in 1 day by 51 pounds per 1,000 pounds 
of weight; No. 616, by 40 pounds; No. 640, by 90 pounds; No. 639 
was poisoned in 2 days by 91.1 pounds ; and No. 647, by 81.1 pounds. 
These differences are made more striking when we find that No. 639 
ate 62.2 pounds the first day, and No. 647 ate 46 pounds. All these 
animals were of approximately the same age, treated in the same 
way with larkspur gathered from the same place, and all were fed 
within 6 days. The difference may be due in part to the condition of 
the animals when receiving the plant, for it is reasonable to assume 
that the rapidity of absorption may be affected by the condition of 
the alimentary canal and its contents. The condition of the excreting 
glands, too, may profoundly modify the toxic effect of the plants. 
Other minor factors doubtless come into play, which may be grouped 
together under the 
general term " the 
varying susceptibil- 
ity of the individual." 
In this connection 
it may be noted that 
apparently rumina- 
tion did not neces- 
sarily precede intoxi- 
cation. While com- 
plete notes were not 
kept on this subject, 
it was definitely 
known that some of 
the animals which 
were poisoned in a short time did not ruminate at all. The minimum 
toxic dose, then, is about 30 pounds, and the average of the three 
seasons about 84 pounds, with a maximum of 280 pounds. This 
maximum, of course, would run to infinity late in the season. In the 
practical handling of cattle it is dangerous for an animal to eat more 
than 3 per cent of its weight in one day, although it may eat two or 
three times as much before showing signs of intoxication. 
The figures, as given above, in regard to the toxic dose apply to 
Delphinium barbeyi and Delphinium menziesii, and it is interesting 
also to note that the quantity necessary to produce poisoning in the 
case of Delphinium menziesii does not differ materially from the 
quantity in the case of Delphinium barbeyi. In the single experi- 
ment with Delphinium robustum 40 pounds per 1,000 pounds of 
weight of the animal produced poisonous effects. Inasmuch as this 
feeding was rather late in the season, this single experiment would 
indicate that Delphinium robustum might be rather more poisonous 
than the two species experimented with at Mount Carbon. It is 
1 
5 1 
S 20 25 30 5 /O /S 20 25 30 S /O 
100 
^ 90 
$ SO 
§ G0 
X so 
$ 40 
30 
© 
i 
> 
i 
i 
9 

• 
Fig. 12. — Chart of feeding Delphinium barbeyi to cattle 
experimentally poisoned in 1911, based on weekly aver- 
ages. The weights of plant are given per thousand 
pounds of animal. 
