122 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 



OPISTHOGLYPHOUS COLUBRID^E. 



The characteristics of Opisthoglyphs have already been considered phylogen- 

 etically in an earlier chapter of this work and they have been shown to occupy 

 intermediate rank between the harmless and the venomous snakes. In fact, 

 opisthoglyphs are of the lowest order of the poisonous snakes, and are not to 

 be "suspected" as poisonous any longer. Medical practitioners have little 

 practical interest in these snakes, as the accidents from their bite are trifling, 

 with little or no danger to human subjects. But it seems quite proper to 

 record here certain well-known observations made by different herpetologists 

 as to the fatal results of their bites upon some small animals. The observa- 

 tions reproduced here are classic, because it was these that decided in the 

 affirmative the long-standing dispute over the toxicity of these reptiles. The 

 records of the observations are abstracted from the admirable work of Stejne- 

 ger on ''Poisonous Snakes of North America." 



Peracca and Deregibus 1 made special investigations into the possible ven- 

 omous nature of Ccdopeltis monspessulana s. lacertina s. Malpolon insignitus. 

 The victims consisted of lizards, frogs, and toads. The snake did not bite 

 voluntarily, and it was necessary to open its mouth and force the animal into 

 its throat; whereupon the snake inserted the venom. The act of biting lasted 

 some moments, and the snake repeated this act several times without allow- 

 ing its prey to escape. The animals were bitten in the hind leg; in the case 

 of the frog the skin had to be removed from the part to be bitten, as the irri- 

 tating secretion of the skin appeared to be particularly distasteful to the 

 snake. 



The symptoms following the bite are described as (i) the suspension of 

 respiration, which usually occurs in a very few minutes (13 minutes being the 

 maximum in a toad) and may happen suddenly or may be preceded by a 

 gradual sinking, interrupted by a deep-breathing pause ; (2) the cessation of 

 reflex movements in the bitten limb, while still persisting for some time in the 

 rest of the body. Irritability of the nerves in the bitten limb soon disappears 

 and general paralysis ensues. Convulsions are rarely seen. The heart con- 

 tinues to beat for a long time, although its strength is much decreased. The 

 muscle around the point of the wound is livid and not excitable. Death 

 ensues generally in half an hour or less. 



An interesting but equally convincing observation on the venomous nature 

 of the bite of Trimorphodon biscutatus has been made by Duges. 2 



One day when I was admiring the snake I saw him seize a Cnemidophorus sex- 

 lineatus, at the middle of the body, advancing his jaws so as to bring the corner 

 of the mouth in contact with the body of the lizard; for several moments he chewed 

 (a rare occurrence in a snake) his victim without the latter moving, letting go 

 after having killed it; but at this juncture the saurian was swallowed by another 

 snake (Ophibolus doliatus) which was kept in the same cage, thus preventing me 

 from finishing the observation A few days after, the same Trimorphodon caught 



1 Peracca and Deregibus. Giornale della R. Accademia di Medicina di Torino, XXXI, 1883, 379. 



2 A. Duges. La naturaleza (Mexico), 1884, VI, 145. 



