OPISTHOGLYPHOUS SNAKES. 2JI 



the study of the symptoms and lesions produced in the various 

 domesticated animals by the venoms of the commoner South 

 African snakes, and during the course of this work I was enabled 

 to investigate more fully the question of the ability of the boom- 

 slang to inflict a bite dangerous to the larger mammals, and, 

 inferentially, to man. 



This investigation was afterwards extended to certain other 

 opisthoglyphous snakes, and the experiments, although at present 

 incomplete, have yielded a number of interesting results. 



In the first place, it was decided to allow the snake which was 

 being tested actually to bite the experimental animals, and this 

 method was chosen as reproducing, as far as possible, natural 

 conditions with regard to the dose of the venom employed, and 

 the method of its introduction into the animal tissues. 



This was of particular importance in dealing with the 

 opisthoglypha, on account of the relatively small size of the poison 

 gland, and of the peculiar dentition. 



The injection of known quantities of dried venom, on the 

 other hand, should, in future experiments, yield valuable informa- 

 tion with regard to the minimum lethal dose, and must be utilised 

 for the more detailed study of the effects produced on particular 

 systems, organs, and tissues. 



For manipulating large snakes, such as boomslangs, we 

 generally employ a pole about six feet in length, fixed near one 

 end by two holes, about one inch apart. A stout cord, knotted at 

 one end, is passed through the two holes, and the snake is held, 

 a few inches behind the head, in the loop thus formed. 



The further end of the pole, together with the loose unknotted 

 end of the cord, may be held in one hand, and with the other 

 hand it is advisable to secure the tail of the snake. 



Smaller snakes, such as schaapstekers, are more easily held 

 with forceps, or with the hand, but mechanical means are generally 

 to be preferred for our purpose, as it is then possible to allow the 

 snake greater freedom to strike. 



The snake, secured by one of the above-described methods, 

 was brought into contact with a selected region of the experi- 

 mental subject, and allowed to bite freely; in some cases it was 

 necessary to irritate the snake before any attempt to bite was 

 made. 



The bitten animal was then placed in a loose box and freed 

 as far as possible from all restraint, and the clinical symptoms 

 exhibited were noted at short intervals. 



There are some twenty-two species of Opisthoglypha recorded 

 as having been found in South Africa, and of these we were able 

 to make observations on the following:— 



i. Displwlidits typus, the boomslang. 



2. Trimerorhinus rhombcatus, the rhombic schaapsteker, 



3. Trimerorhinus tritacniatns, the striped schaapsteker. 



4. Lcptodira hotambaeia, the herald or red-lipped snake. 



5. Psammophis furcatus, a sand snake. 



6. Tarbophis semiannulatus, the tiger snake. /\A «« 



