POISONOUS PROPERTIES OF THE WHORLED MILKWEED. 13 
Of the sheep, 534 was only slightly sick, and 372 and 522, in both 
experiments, showed only symptoms. The average time of the sheep 
cases was between 4J and 4§ hours, with a minimum of 1 hour and a 
maximum of 11 hours. The symptoms persisted longer in the more 
pronounced cases. 
It was shown on page 7 that the A. pumila cases continued from 
7 J hours to 5 days, and on page 7 that A. verticillata var. geyeri cases 
varied from 1 to 4 days, averaging 2 days and 8 hours. 
If sheep poisoned by A. galioides recovered they were sick only a 
few hours, while with both A. pumila and A. verticillata var. geyeri 
the symptoms continued for a prolonged period. 
Inasmuch as in all the whorled-milkweed cases the symptoms con- 
tinued longer in the more pronounced cases, and as A. galioides is 
vastly the most toxic of the three species, one would expect the 
A. galioides cases to continue the longest. This unexpected result is 
a matter of a good deal of interest, and there is reason to think that 
it will be explained by the detailed chemical study of these plants, 
which is now in progress. 
TOXIC DOSE. 
The leaves and stems of the plant (A. verticillata var. geyeri) were 
given by the balling gun to 10 sheep. As Asclepias galioides had been 
found to be extremely toxic, the experiments were commenced with 
small closes, which were gradually increased until results Avere ob- 
tained. No effect was produced until Sheep 473 became very sick 
on 2.205 pounds per hundredweight of animal. As Sheep 556 was 
not affected by 2.021 pounds, nor Sheep 546 by 2.113 pounds, it is 
a fair inference that 2.205 pounds is very close to the toxic dose. The 
smallest toxic dose of Asclepias galioides is 0.22 pound, while the 
smallest toxic dose of Asclepias pumila. is 0.787 pound. Asclepias 
verticillata var. geyeri, then, is about one-third as toxic as A. pumila 
and about one-tenth as toxic as A. galioides when leaves and stems 
are fed. 
In feeding the leaves of the plant by the balling gun the smallest 
dose was 1.286 pounds. The smallest toxic dose of A. galioides leaves 
fed in the same way was 0.138 pound, so that in this case the A. 
galioides was about nine times as toxic as the A. verticillata var. 
geyeri. 
COMPARATIVE TOXICITY OF STEMS AND LEAVES. 
It may be noted that, as shown in the preceding paragraph, when 
leaves and stems are fed together the toxic dose is 2.2 pounds, while 
with leaves alone it is 1.378 pounds. This difference, of course, is 
due to the greater toxicitv of the leaves. This is a matter of a great 
deal of interest, for extended experiments on A. galioides carried 
on since the publication of Bulletin 800 have conclusively shown a, 
