MEXICAN WHORLED MILKWEED AS A POISONOUS' PLANT. 5 
Table 1. — Summary of feeding experiments with Asclepias mexicana {air-dried plant fed 
with balling gun; no remedies used). 
Animal. 
Date of 
feeding. 
Part of plant used. 
Weight 
of plant 
estimated 
as green 
plant 
per 100 
pounds of 
animal. 
Result. 
Designation. | Weight. 
Place and date of 
plant collection. 
Pounds. 
Sheep 5S2 ... 98 
1920. 
June 21 
June 23 
June 28 
July 1 
July 6 
...do 
July 8 
July 13 
July 14 
July 16 
July 20 
July 22 
Aug. 10 
Aug. 13 
Aug. 23 
Aug. 31 
Sept. 3 
Sept. 9 
Sept. 13 
Pounds. 
0.176 
. 353 
.529 
.705 
.705 
.882 
.882 
1.058 
1.323 
1.411 
1.764 
1.481 
.882 
1.058 
1. 235 
1.543 
1.323 
2.205 
3.527 
Not sick 
Sickness 
do 
do 
Not sick 
Mount Diablo,Calif., 
Sheep 588 
Sheep 595 
Sheep 603 
Sheep 607 
Sheep 610 
Sheep 563 
Sheep 579 
Sheep 5M 
Sheep 584 
Sheep 586.... 
Sheep 595 
Sheep 568 
Sheep 575 
Sheep 580 
Sheep 590 
Sheep 595 
Sheep 602 
93 
78 
97.75 
93 
81.75 
102.5 
86 
75. 5 
82 
128 
81 
86 
72.25 
69 
103.5 
92 
93. 25 
do 
do 
do 
fall of 1919. 
Solano, Calif., fall of 
1919. 
Do. 
Do. 
Do. 
Do. 
Not sick 
....do 
Do. 
.do 
Do. 
.do 
Slight sickness. 
Not sick 
Slight sickness. 
Not sick 
Mount Diablo,Calif . 
do 
do 
do 
Leaves, stems, and 
flowers. 
Leaves, stems, and 
flowers. Large 
proportion of 
stems. 
Leaves, stems, and 
flowers. 
do 
.do 
fall of 1919. 
Do. 
Mount Diablo and 
Solano, Calif., fall 
of 1919. 
Solano, Calif., fall of 
1919. 
do 
July, 1920. 
Do. 
do 
Do. 
Death 
Do. 
....do 
Do. 
Symptoms 
Possible symp- 
toms. 
Do. 
Sheep 603 106. 5 
do 
Do. 
TYPICAL CASE, SHEEP 610. 
Sheep 610 was a ewe weighing 81.75 pounds at the time of the exper- 
iment. She had not been used in any other experimental work. To 
this animal was given by the balling gun, between 5.07 and 5.15 p. m., 
on July 6, 87.75 grams of dry Asclepias mexicana leaves, an equivalent 
of 0.882 pound of green plant per 100 pounds of animal. When 
observed at 6.25 a. m. July 7 she was unsteady, staggering as she 
walked about. At 7.20 a. m. the unsteadiness had increased in a 
marked degree. At 8.59 a. m. her temperature was 105° F., pulse 
152, respiration 36. When observed between 1.10 and 1.30 p. m. 
she could move about without falling, but staggered, and when mov- 
ing about went with a sidling gait, the weakness being most pro- 
nounced in the hind legs. Plate II, figure 1, shows very clearly this 
weakness in the hind legs. This condition continued during the after- 
noon and evening. At 5.33 p. m. the temperature was 103, pulse 
140, and respiration 44. 
On July 8 at 8.30 a. m. she appeared somewhat better than on the 
preceding day. At 9.36 a. m. the temperature was 102.4, pulse 120, 
