THE WHOKLED MILKWEED AS A POISONOUS PLANT. 21 
the water-soluble fraction, and the substance which causes the spas- 
modic symptoms observed in animals. After a complicated manipu- 
lation the last substance was obtained as a colorless, brittle, resinous 
mass which has not yet yielded anything of a crystalline nature. It 
melts indefinitely at about 60° C, is insoluble in water, aqueous acids, 
and alkalies, is very soluble in alcohol, amyl alcohol, glacial acetic 
acid, acetone, chloroform, ether, benzol, acetic ether, and pyridine. 
It does not appear to be glucosidal. Further investigation, with the 
object of determining its precise chemical nature, is in progress. 
This substance has been thoroughly tested upon guinea pigs and 
produces the characteristic symptoms observed on the range, with the 
typical lesions. 
Fresh samples of the plant were tested for the presence of volatile 
poisons and toxic saponins, with negative results. 
PHARMACOLOGICAL RESULTS. 
The pharmacological work w T as conducted according to the follow- 
ing plan : Each of the various fractions resulting from the chemical 
treatment of the plant extracts was administered through the mouth 
to an animal. Extracts which contained much matter insoluble in 
water were emulsified in that liquid with either acacia or mucilage of 
Irish moss ; soluble extracts were given in water solution. Frequent 
control animals served to exclude accident. 
The animals used were sheep and guinea pigs. The larger propor- 
tion of the testing was done with the latter animals, which were 
found to react excellently and characteristically to the toxins of the 
plant, duplicating the symptoms observed in the experimental sheep 
almost to the most minute detail. In indefinite cases the tests were 
repeated upon several animals; 126 experiments in all were con- 
ducted. As criteria in the work upon the guinea pigs were taken 
the symptoms and pathological lesions exhibited by the experi- 
mental sheep. By following this plan it was found possible to 
exclude many of the plant constituents as innocuous or as not factors 
in range poisoning and to locate definitely the fractions which con- 
tain toxic substances. 
Three general and distinct types of intoxication were observed in 
guinea pigs which were drenched with toxic fractions of extracts 
from this plant. 
The first type closely resembles the typical cases of range poisoning 
which follow the ingestion of the whole plant. This type of intoxi- 
cation is produced by the resinous substance described above ; it com- 
mences with a general weakness, the animal appears disinclined to 
move about, and is soon narcotized. After an interval convulsions 
appear, with the characteristic running movements in many cases 
and the peculiar tendency to fall and lie always on the same side of 
