THE WHOELED MILKWEED AS A POISONOUS PLANT. 13 



HORS£ EXPERIMENTS. 



Only one horse, No. 126, a 5-year-old gelding weighing 1,020 

 pounds and in fine condition, was used for experimental feeding. 

 At 3.36 p. m. July 30, 1918, the animal was given 1,020 grams, equal 

 to 0.22 pound per hundred weight of animal, of Asclepias galioides 

 which had been shipped from Hotchkiss, Colo. The plant w£is mixed 

 with 5 pounds of alfalfa hay. The feeding was entirely eaten by 

 5.15 p. m. of the same day. The horse was kept under observation 

 until 10.30 p. m. and during that time no symptoms appeared. It 

 was seen again the following morning, July 31 at 7.45 a. m,, when 

 it seemed slightly paralyzed in its hind legs and while being driven 

 from one pen to another, fell down. At 8 a. m., its pupils were di- 

 lated and it was moving uncertainly about the corrals, evidently not 

 having entire control of its legs. When hurried it fell. At 8.30 a. m. 

 it was staggering about the corral ; would walk a few steps, tremble, 

 spread its legs apart and fall. As it went down its head was bent 

 toward its breast and its lips were drawn back from its teeth. It 

 perspired freely and the pupils were dilated. These motions were 

 repeated again and again. The animal rose from the reclining pos- 

 ture with difficulty and in its attempt to move about the corral was 

 uncertain in its movements and staggered from side to side. It could 

 stand for only an extremely short time and then would fall and 

 again attempt to rise. 



Plate V, figures 1, 2, 3, 4, 6, and 6, show its attitude at various times 

 between 8.25 and 8.45 a. m. Figure 1 shows the attitude assumed 

 during the spasms. The head is extended rather rigidly and the 

 legs drawn close to the body. In figure 2 the animal is shown in 

 a brief period of rest before attempting to rise. Figure 3 shows the 

 characteristic staggering as it attempted to move about the corral. 

 In figure 4 its head is drawn close to the breast, an attitude frequently 

 assumed in the spasms. In figure 5 the horse is attempting to rise. 

 It was noticed in these attempts that it had less control of the hind 

 legs than of the fore legs. These motions were repeated every 2 to 

 5 minutes and it was noticed that in falling the animal almost in- 

 variably fell upon its right side, -the head sometimes striking the 

 ground with great violence. Figure 6 shows the animal just as it is 

 attempting to raise its head from the ground. 



Plate Va, figure 1, taken at 8.57 a. m., shows the horse in one of 

 its attitudes when attempting to stand. As stated, the animal would 

 fall upon its right side and roll upon its belly and then attempt, 

 with greater or less success, to rise. During this time it breathed 

 with forcible expirations, frequently accompanied with grunts. Fig- 

 ure 2 of the same plate shows the animal again in one of its attempts 

 to get upon its feet. These motions were repeated frequently, the 



