THE WHOKLED MILKWEED AS A POISONOUS PLANT. 25 
examined and the fractions into which the extracts were divided were 
tested for pharmacological activity. 
The investigation has yielded the following preliminary results: 
Asdepias gaMoides appears to contain several toxic compounds, some 
of which are glucosidal in nature. The substance which is respon- 
sible for the symptoms observed in range poisoning may be extracted 
from the plant with cold alcohol and is insoluble in hot or cold water. 
The plant yields water-soluble toxins, probably glucosids, which cause 
narcosis in experimental animals without congestion of the central 
nervous system. 
In addition, the plant contains less than 0.01 per cent of an alkaloid 
which does not appear to be toxic and certainly does not influence the 
range cases. Attempts to discover toxic saponins in the plant were 
unsuccessful. 
PART III.— GENERAL DISCUSSION AND CONCLUSIONS. 
SYMPTOMS. 
Generally speaking, the first evidence of intoxication is the loss 
of control of the muscles. The animal staggers when walking and 
eventually falls and is unable to rise. Sometimes it is found down 
before any other symptons appear. At this time there is, in most 
cases, salivation and there may be marked trembling. 
The horse was in profuse perspiration. The loss of muscular con- 
trol is most marked in the posterior part of the animal. The period 
during which the animal can remain upon its feet is generally very 
short. When down it generally makes strenuous efforts to rise but 
falls back with a good deal of violence. This feature was very 
marked in the case of the horse. It may be noted that in the range 
cases the animals are said to knock their heads on the ground. Soon 
there commences a series of clonic spasms. It is shown by the au- 
topsies that the stomachs are greatly distended with gas, which is 
also true, to some extent, of the intestines. The formation of the gas 
continues during the period of intoxication, with some relief by 
belching and the spasms are correlated with the gas formation. 
The bloat caused by the gas was one of the most noticeable features 
in the poisoned sheep. Vomiting occurred in one case, but was not a 
usual symptom. In the spasms the pupils are widely dilated. The 
spasms may become more or less tetanic in character. Ordinarily the 
animal throws itself repeatedly into a position of opisthotonos, as 
shown in Plate VII, figures 2 and 3, and this may be followed by a 
position close to emprosthotonos. Very characteristic is the posi- 
tion shown in Plate V, figures 1 and 4, in which the chin is brought 
down to the breast in a tetanic spasm. This was shown with especial 
clearness in Horse 126. Generally in this position the feet were drawn 
up to the body as shown in Plate V, figure 1. The spasms are some- 
