14 



BULLETIlSr 969, U. S. DEPARTMENT OF AGEICULTURE. 



The minimuin lethal dose for these animals was 1.323 pounds. 

 This is probably a rather accurate figure, for Sheep 575 received 

 1.058 pounds and Sheep 580 1.235 pounds without fatal results in 

 either case. The minimum toxic dose was 0.882 pound. No experi- 

 ments were made with slightly smaller doses, but as Sheep 568 was a 

 mild case this dose must be not far from the minimum of toxicity. 



Leaves. — Table 5 shows the dosage when leaves only were fed. 



Table 5. — Dosage of A. viexicana, leaves only. 



Animal. 



Sheep 582 

 Sheep 588 

 Sheep 595 



Quantity, 



fed per 100 



pounds of 



animal. 



Pounds. 

 0.176 

 0.353 

 0.529 



Result. 



Not sick. 

 Sickness, 

 do. 



Animal. 



Sheep 603. 

 Sheep 610. 



Quantity 

 fed per 100 

 pounds of 

 animal. 



Pounds. 

 0.705 

 0.882 



Result. 



Sickness. 

 Death. 



As Sheep 603 was not very sick on 0.705 pound, it is probable that 

 0.882 pound, which caused the death of Sheep 610, is close to the 

 lethal dose. While 0.353 pound Was the smallest dose producing 

 sickness, it is possible that it is not the minimum, as there were no 

 tests between that and 0.176 pound which was given without effect 

 to Sheep 582. 



Stems. — Nine sheep were fed on stems from wliich all leaves had 

 been removed, as shown in Table 6. 



Table 6. — Dosage of A. niexicana, stems only. 





Quantity 







Quantity 







Ajiimal. 



fed per 100 

 pounds of 

 animal. 



Result. 



Ammal. 



fed per 100 

 pounds of 

 animal. 



Result. 







Pounds. 







Pounds. 







Sheep 607 



0.705 



Not sick. 



Sheep 586 



1.764 



Slight sickness. 





Sheep 563 



0.882 



do. 



Sheep 595 



1.481 



Not sick. 





Sheep 579 



1.058 



do. 



Sheep 602 



2.205 



Symptoms. 





Sheep 581 



1.323 



Slight sickness. 



Sheep 603 



3.527 



Possible symptoms. 





Sheep 584 



1.411 



Not sick. 











The smallest quantity of stems fed which produced symptoms was 

 1.323 pounds. As compared with this, Sheep 584 and Sheep 595 

 showed no effect from 1.411 pounds and 1.481 pounds, respectively. 

 The table shows also that as much as 3.527 pounds was fed to Sheep 

 603 with only slight effect. No animals were killed by the feeding of 

 stems. It appears then that as little as 1.323 pounds may produce 

 slight symptoms. The lethal dose has not been determined, but it 

 probably is several times this quantity. 



For comparative purposes the toxic and lethal doses of whole plant, 

 leaves, and stems to 100 pounds of animal may be tabulated as 



lOilOWS; Minimum toxic Minimum lethal 



dose. _ dose. 



Pounds'. Pounds. 



Leaves 0.353 . 0.882 



Wlioletop 0.882 1.3 



Stems ,.,.,.,.,-.,... 1, 323 More than. .....,..,. 3. 5 



