LARKSPUE POISOlSrilSrG OP LIVE STOCK. 



71 



results: No. 637 was poisoned in 1 day by 51 pounds per 1,000 pounds 

 of weight ; No. 646, 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 harheyi and Delphinium menziesii, and it is interesting 

 also to note that the quantity necessary to produce poisoning in the 

 case of Delphinium memiesii does not differ materially from the 

 quantity in the case of Delphiniumi harbeyi. In the single experi- 

 ment with Delphinium^ rohustum 40 pounds per 1,000 pounds of 

 weight of the animal produced poisonous effects. Inasmuch as this 

 i;eeding was rather late in the season, this single experiment would 

 indicate that Delphinium rohustum might be rather more poisonous 

 than the two species experimented with at Mount Carbon. It is 







JU/ 



1 







5 1 



S BO 25 30 S /O IS 20 ZS 30 S lO 



100 

 ^ 90 

 ^ SO 

 % '^0 



§ ^° 

 1 so 



^ 40 

 30 



























































• 



























' 

















< 







































































































• 















• 















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...-., 





























Fig. 12. — Chart of feeding Delphinium harbeyi to cattle 

 experimentally poisoned in 1911, based on weekly aver- 

 ages. The weights of plant are given per thousand 

 pounds of animal. 



