OPISTHOGLYPHOUS SNAKES. 275 



tissue around the bite and over two small areas on the abdominal 

 wall. 



2. Froth in the trachea and bronchi, and some pulmonary 

 oedema. 



3. Liver parenchyma pale and soft, with some small haemorr- 

 hagic areas. 



4. Kidneys — numerous small haemorrhages under the capsule 

 and in the medulla, but particularly numerous in the cortex. 



5. Petechia; and haemorrhagic streaks in the omasum, abo- 

 masum, and jejunum, and particularly in the caecum and colon, 

 the contents of which were deeply blood-stained. 



In these and the other fatal cases observed by me, the most 

 striking feature in the process is the long period which may 

 elapse before the onset of symptoms, and the marked effect on 

 vascular endothelium. 



In no case did I see any symptoms pointing very clearly to 

 the action of a potent neurotoxine ; dullness, depression, and 

 some evidence of local pain at the site of the bite, were the only 

 nervous symptoms noted. 



With regard to the action on the blood, the boomslang venom 

 appears to exert some anti-coagulative, and slight haemolytic 

 action in vivo. 



From clinical observation, it would appear that death occurs 

 chiefly as a result of the exhaustion consequent upon extensive 

 haemorrhage, and it can no longer be seriously doubted that the 

 boomslang is able to inflict a bite fatal to man and the larger 

 domesticated animals, provided that the snake is able to secure 

 a favourable hold. 



Such a conclusion has a certain amount of practical import- 

 ance, and is of great interest on theoretical grounds, but I do not 

 think that boomslangs are likely to cause many deaths among 

 human beings. 



In the first place, the boomslang is generally (but not always) 

 a very timid snake, and unlikely to bite a large animal unless 

 actually seized or cornered. 



In the second place, it is necessary, on account of the peculiar 

 dentition, that the boomslang should have the opportunity of biting, 

 to the full extent of the jaws, on a part without any protective 

 covering of even moderate thickness, and that it should be able 

 to retain this hold over a period of several minutes. 



In fact, the opisthoglypha generally show quite a character- 

 istic mode of biting, very notably different from that of the 

 pioteroglyphous snakes, and demanding much more favourable 

 circumstances for its infliction than is the case with the latter. 



2. Trimerorhhnis rhombeatus and tritccniatus, the schaap- 

 stekers. 



Repeated experiments on guinea-pigs and rabbits have shown 

 that theschaapstekers are able to inflict a bite rapidly fatal to 

 such animals, the time elapsing before death varying, in our 

 experiments, from seven to forty minutes. 



The symptoms are quite characteristic: after a period of 



