8 
BULLETIN 969, U. S. DEPARTMENT OF AGRICULTURE, 
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 588 , 
Sheep 595 (June 28). 
Sheep 603 (July 1)... 
Sheep 610 
Sheep 581 
SheeD586 
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 
1.543 
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 
Slight sickness. 
....do 
Sickness.... 
....do 
....do 
Death 
....do 
Symptoms . 
do 
II. m. 
16 25 
13 10 
15 10 
15 37 
14 51 
12 45 
12 45 
12 55 
12 45 
12 50 
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 varied from 2J 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 wider 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. 
