ZYGADENUS, OR DEATH CAMAS. 33 



The seeds are very much more poisonous than any other part of the 

 plant. Heyl, Loy, Knight, and Prien (1912, p. 17) give the results of 

 determinations of alkaloids- in different parts of the plant. Their 

 statement is obscure and contradictory, but apparently they reach 

 the conclusion that the bulbs and leaves contain approximately the 

 same quantity of the alkaloid, the roots much less, and the flowers 

 about twice as much as the bulbs and leaves. This compares very 

 well with the results of the experimental feeding at Greycliff, except 

 that it did not appear that the flowers were more toxic than other 

 parts of the plant. 



Table II gives the maximum and minimum dosage, and it will 

 be noticed that there is a considerable range of variation between 

 these two. The individual peculiarities of the animal in cases of 

 poisoning doubtless must be taken into account, and the detailed 

 table of the experiments shows that in some cases a larger quantity 

 of plant than that which this table indicates to be toxic may be 

 administered without effect. In most of the cases, however, where 

 the larger amount was used, the feeding was distributed over a 

 longer time. 



In general, the experiments seem to indicate that when any part 

 of the plant except the seed is used the toxic dose varies from 1..6 

 pounds per hundredweight of animal to 5.6 pounds, this wide range 

 of variation being accounted for by the more or less extended time 

 of feeding. In the drenching and forced-feeding experiments, more 

 uniform results were reached, showing that the toxic dose of all parts 

 of the plant, except the seed, is not far from 0.5 pound per hundred- 

 weight of animal. 



There is considerable difference in the items of the summarized 

 tables in the exactness of the averages, and some explanation is 

 necessary to indicate their actual value. 



In the feeding of leaves in 1914, there were three cases, two 

 becoming sick. The third case received 0.661 pound without symp- 

 toms, the same quantity that was received by No. 282, which became 

 sick. It seems probable, then, that the average figure 0.6615 must 

 be pretty close to the toxic limit. In the feeding of " leaves and some 

 young buds" in 1914, while the minimum of sick cases received 0.499 

 pound, another animal received 0.551 pound without ill effect; it is 

 evident that the toxic limit must be not far from 0.5 pound. In the 

 feeding of eight cases on "leaves, stems, flowers, and buds/' with 

 material collected near the station, the toxic limit was practically the 

 same as in the preceding cases. A perusal of Table II shows that 

 during the growth of the seed heads the toxicity was reduced and 

 that the fully developed seed heads were somewhat less toxic than 

 the plant in the earlier stages. 



