BULLETIN 969, U. S. DEPAKTMENT OF AGPJCULTUEE. 



come down somewhat slowly, as these do, it is not easy to distinguish 

 the very beginning of symptoms. The shortest time was 12 hours 

 and 45 minutes, occurring in three cases, and they were sick when 

 first observed in the morning following the feeding. 



Table 2. — Time elapsed between feeding of plant and development of symptoms,. 



Animal. 



Quantity 

 per 100 

 pounds 



of 

 animal. 



Part of plant used. 



Result. 



Time 

 elapsing 

 before 

 symp- 

 toms. 



Sheep 688 



Sheep 59-5 (June 28). 

 Sheep 603 (Tuly 1)... 



Sheep 610 



Sheep 581 



SheeD.586 



Sheep 568 



Sheep 575 



Sheep 580 



Sheep 590 



Sheep 595 (Sept. 3).. 



Sheep 602 



Sheep 603 (Sept. 13). 



Average 



Pounds. 

 0.353 

 0.529 

 0. 705 

 0.882 

 1.323 

 1.764 



0. 882 

 1.058 

 1.235 

 1.5^3 



1. 323 

 2.205 

 3. 527 



Leaves 



do 



do 



do 



Stems 



do 



Leaves, stems, and flowers. 



do 



do 



do 



do 



Stems 



do 



Sickness 



do 



do 



Death 



SUght sickness. 



do 



Sickness 



do 



do 



Death 



do 



Sjinptoms 



do 



//. TO. 



14 40 



14 45 

 16 25 



13 10 



15 10 

 15 37 



14 51 

 12 45 

 12 45 

 12 55 

 12 45 



12 50 



13 49 



14 



The time elapsing before symptoms in A. galioides was 14 hours 

 and 6 minutes; in A. pumila 16 hours and 17 minutes; and in A. 

 verticillata var. geyeri 16 hours and 47 minutes. 



The average time in all the species of whorled milkweed was much 

 the same. There was, however, much more variation in limits of 

 time in the other species. A. galioides YSiried from 2^ to 21 hours, 

 A. pumila from 12 hours and 37 minutes to 30 hours and 15 minutes, 

 and A. verticillata var. geyeri from 14 hours and 10 minutes to 20 

 hours and 35 minutes, while A. mexicana varied only from 12 hours 

 and 45 minutes to 16 hours and 25 minutes. 



A comparison of these figures with those in Fleming and co-authors 

 (1920, pages 15 to 17), shows a good agreement in averages. In Table 

 I on feeding of green plant the average time from feeding to symptoms 

 was 15 hours and 27 minutes. The combined average of Tables II 

 and III of feedings of dry plant was 14 hours and 48 minutes. This 

 latter average is obtained on the assumption that the time of feeding 

 of Sheep No. 8 was probably 2.50 p. m. instead of 2.50 a. m., as given 

 in the Nevada bulletin. 



There is, however, a wicier range of variation than in the work at 

 the Salina Experiment Station, the minimum being 1 hour and 50 

 minutes, and the maximum 23 hours and 20 minutes. The large max- 

 imum figures are doubtless explained, in part at least, as stated in the 

 Nevada bulletin, by the fact that no night observations were made, 

 so that in many cases the time of the beginning of symptoms was not 

 noted. The minimum figures in most cases are correlated with very 

 heavy doses. 



