24 



BULLETIN 1012, U. S. DEPARTMENT OF AGRICULTURE. 



green weight the figures for the dosage of Sheep 199 and 185 should 

 be multiplied by four. This makes the dosage compare fairly well 

 with the 1920 experiments. 



COMPARATIVE TOXICITY OF Z. GRAMINEUS Z. PAXICULATUS, AXD Z. ELEGANS. 



From the somewhat insufficient data of the experimental work 

 there have been tabulated the smallest effective doses in sheep of the 

 three species of Zygadenus which have been examined. All these 

 cases were of forced feedings with the exception of the feeding of 

 seed of Z. gramineus. 



TABLE 11. Comparative toxicity of Z. gramineus, Z. paniculatus, and Z. elegans; 



minimum effective dosage. 



i Fed. 



Table 11 shows those cases which received similar material. It is 

 impossible, of course, to determine from a table of this character the 

 relative toxicity of the plants with any degree of exactness. It ap- 

 pears, however, that, put in a general way, Z. gramineus is three 

 times as toxic as Z. paniculatus, and seven times as toxic as Z. elegans. 

 It is interesting to note that, so far as the experiments are concerned, 

 the toxicity of the seed of Z. gramineus and Z. paniculatus is practi- 

 cally the same. 



COMPARATIVE TOXICITY OF FRUIT AXD SEEDS OF Z. PAXICULATUS AXD Z. ELEC1AXS. 



Ripe fruit heads of both Z. paniculatus and Z. elegans were col- 

 lected and the seed separated from the pods and weighed. In both 

 species it was found that very close to one-half of the dry weight was 

 seed. In one collection of nearly ripe Z. elegans the fruit heads were 

 weighed separately from the rest of the plant and found to be 23.4 

 per cent of the entire plant exclusive of the bulbs and roots. From 

 this it appears that in Z. elegans close to 11.7 per cent of the weight 

 of mature air-dried plant is seed. 



The comparative toxicity of fruit heads and seed of Z. paniculatus 

 shows that most of the toxic element of the fruit heads is in the seed. 

 Sheep 569 was made very sick on 0.661 pound of green fruit heads, a 

 sample of which lost 77 per cent in drying. This, then, was equiva- 

 lent to 0.152 pound of dry material. Sheep 609 was made sick on 

 0.124 pound of dry fruit heads. Sheep 583 was made very sick on 



