28 
The Bulletin 
capsule and its contents. This method of administering the products 
of white snakeroot was abandoned for a more convenient one in the 
other experiments. All materials not already in liquid form were dis¬ 
solved in water and were allowed to drop from a pipette into the guinea 
pigs’ mouths. 
In expressing the sap or juice from white snakeroot, use was made 
of a small meat chopper. The green weeds were passed through this 
meat chopper which had been fitted with a plate having small open¬ 
ings. The rotation of the cylinder which fed the machine pressed the 
macerated weeds through these small openings and at the same time 
pressed out the plant sap. The sap escaped through the crevice between 
the rotating cylinder and the frame of the chopper, that is, in the 
direction opposite that in which the “pomace” or residue escaped. 
Post-mortem examinations were made of twenty-two of the thirty-one 
sheep which died of the disease. Thirty of these animals were observed 
to tremble in the characteristic manner. With the exception of ewe 
Ho. 169 and lamb Ho. 237, both of which had stomach worms (Hemon- 
chus contortus), there was no evidence that death resulted from causes 
other than the feeding of E. urticsefolium. Both of these animals mani¬ 
fested characteristic symptoms of trembles, however. Post-mortem ex¬ 
aminations were furthermore made of all other animals which died 
during the course of the experimentation and certain of the internal 
organs were also preserved for microscopic study. A detailed report 
covering studies on some of these tissues has been prepared and is 
representative of all cases examined. 
Results of Experiments 
a. With Sheep 
Experiment 1 .—Three ewes, Hos. 11, 26, and 10, were used in Ex¬ 
periment 1, a preliminary experiment which was designed to determine 
whether harmful effects follow the feeding of E. urticEefolium. This 
experiment was begun on June 17 and closed on August 2. However, 
from June 22 to July 6 and from July 18 to July 28, it was impossible 
to secure the weed. During these periods the animals were grazed on 
Bermuda grass pasture. Except during the two periods mentioned, a 
liberal supply of white snakeroot was fed just as it arrived from the 
point of shipment. In addition, a maintenance ration of grain was fed 
in a separate trough. Heither the weeds nor the grain were weighed in 
this experiment. Initial and final weights of each animal were recorded. 
In the period between June 17 and July 16, ewe 11 was fed on white 
snakeroot and grain for an aggregate of fifteen days. A typical case 
