27O OPISTHOGLYPHOUS SNAKES. 



The difficulty for the uninformed of differentiating between 

 many genera and species, together with the serious results conse- 

 quent upon errors in this respect, has, however, led to the develop- 

 ment of a feeling of horror and repulsion which is, with some 

 notable exceptions, more or less general among the human race, 

 and the majority of human beings are wont to regard all snakes as 

 dangerous enemies. 



The growth of zoological science, with the introduction of 

 systematic classification, soon led herpetologists to recognise that 

 the proteroglyphous Colubridse, and the Viperidae, are especially 

 adapted for the infliction of venomous bites, and that such a feat 

 is impossible to the solid-toothed colubrine. 



In the opisthoglyphous snakes they recognised the existence 

 of an earlier stage in the development of a specialised poison-gland, 

 and of the modified dentition necessary to facilitate the introduc- 

 tion of the secreted venom into the tissues of the prey attacked. 



They have considered, however (unanimously, I think), that 

 these snakes are unable to inflict a bite of such a character as 

 seriously to endanger the life of man or of the larger mammals. 



Thus Calmette, in his classical work on venoms, writes : — 

 Presquc tous les serpents classes dans ces trois sons-families [i.e., 

 the three sub-families of the opisthoglypha I sont venimeux, mais a un 

 faible degre. lis nc sont pas dangereux pour I'homme. Leur venin ne 

 fait que paralyser leurs proies avant la deglutition : il ne constitue pas 

 pour eux tin moyen efficace de defense ou d'attaque. 



And again, in speaking of the sub-family Dipsodomorphinae, 

 he remarks : — 



Aucun de ces reptiles n'est susceptible d'occasionner d'accidents 

 serieux chez I'homme, a cause de la disposition particulierement defectueuse 

 de leur appareil venimeux. 



Popular opinion in South Africa has generally ascribed veno- 

 mous powers to certain opisthoglyphous snakes, and particularly 

 to the boomslang and the schaapstekers, and there have been 

 more or less circumstantial reports of serious illness, and even 

 death, occurring in man as a result of a boomslang bite. 



In view of the unreliability of popular evidence, frequently 

 distorted and obscured by incomplete observation and prejudice 

 (the latter especially in any matter relating to snakes), these 

 reports attracted but little notice. 



In recent years Mr. Fitz Simons has recorded the case occur- 

 ring in the Port Elizabeth Museum, where Mr. Williams nearly 

 lost his life as the result of a bite from a boomslang, and Mr. 

 Fitz Simons performed a number of experiments on fowls and 

 small animals, showing that the bite of the boomslang was 

 undoubtedly fatal to such animals. 



The case of Mr. Williams, however, stood alone, and lacked 

 the confirmation which would be afforded by the production of 

 similar symptoms in the larger mammals, and in animals more 

 closely allied to man. It might, therefore, be considered to be a 

 mere coincidence, or as a case of some septic infection of the 

 wound inflicted. 



In the year 191 1, Dr. Theiler suggested that I should take up 



