1902.] Properties of Saliva of " Non-poisonous " Colubrines. 449 



Finally we have to explain that we used the extract of the parotid 

 gland because, even with Opisthoglyphous snakes, we were unable to 

 devise any satisfactory way of getting parotid secretion free from the 

 ordinary saliva of the labial glands. 



IT. Details of Experiments. 



A. Experiments with Opisthoglyphous Colubrines. 

 i. Cerberus rhynchops. 



Experiment 1. — A white mouse was injected under the skin of the 

 back with the watery extract of both parotid glands of a full-grown 

 snake. Ten minutes afterwards it was sluggish, 17 minutes afterwards 

 it was lazy and sleepy, and 22 minutes afterwards its hind legs were 

 partially paralysed. In 24 minutes the respirations were at the rate 

 of forty in 15 seconds, and the animal could not stand. In half an 

 hour convulsions began, and the respirations were thirty-seven in 

 15 seconds. At the 32nd minute the respirations had fallen to fourteen 

 in 15 seconds, and at the 34th minute they had stopped. Thirty-six 

 minutes after the injection the heart stopped also. 



Post-mortem. — There was very marked subcutaneous extravasation of 

 blood over the whole of the back. 



No control experiments with blood-serum or with the secretion of 

 other glands were made. 



ii. Dipsas Forstenii. 



Experiment 2. — A black-and-white mouse was injected under the 

 skin of the back with the watery extract (4 minims) of one parotid 

 gland of a full-grown snake. Twelve minutes afterwards spasmodic 

 twitchings began. In another minute the animal turned over on its 

 side, still twitching, and its respirations were thirty-eight in 15 seconds. 

 At the 14th minute it could not stand, and its breathing became slower. 

 At the 16th minute the respirations were seven in 15 seconds, and very 

 laboured. At the 17th minute the heart was beating fast, though the 

 breathing was occasional and convulsive. At the 21st minute after 

 injection the breathing had stopped, and at the 23rd minute the 

 heart. 



Experiment 3. — As a control experiment, a white mouse was injected 

 under the skin of the back with the watery extract (4 minims) of one 

 Harderian gland of a Dipsas Forstenii. Thirteen minutes afterwards 

 the animal appeared to be slightly sleepy, but no definite symptoms of 

 poisoning were seen within the next hour, and the following day it was 

 quite well. 



