THE LIVING WORLD. 
158 
duced death in seven minutes. On a second trial a small quantity was injected 
into the carotid artery of a rabbit, the animal dying in one minute and thirty- 
five seconds. Different from the action of serpent-poison, which affects the respi¬ 
ratory functions, the poison of the heloderma attacks the heart and the spinal cord. 
The power of this portion of the nervous system to respond to even powerful 
electric currents is abruptly annihilated.” 
Though the opinions of these two distinguished naturalists are in opposi¬ 
tion, yet they are both right from the standpoint of . their respective examina¬ 
tions. I have seen dozens of these creatures, and have regarded them with no 
more fear than our ordinary lizards, nor have I ever seen any fear of them 
exhibited by the natives of the region in which the heloderma is found. Still, 
I would not deny they are venomous, though the declaration needs some quali- 
ICHTHYOSAURUS, PLESIOSAURUS AND PTERODACTYL. 
ffication. I have never seen the experiment made, but reasoning from observa¬ 
tion I am of the opinion that the secretion of the common toad is poisonous, 
and if injected into the breast of a pigeon might produce serious symptoms, 
though probably not death. The same is true of the secretion of the salaman¬ 
der, which is undoubtedly a provision of nature to protect the creature from its 
enemies. But this fact is not sufficient to class them among the venomous 
reptiles. On two different occasions I sought to provoke a company of six 
helodermas to anger, with the view of discovering the manner in which they 
use, and the strength of, their jaws. For this purpose I used a stick and piece 
•of heavy wire, but notwithstanding the teasing and tormenting not one offered 
the slightest resistance. I next made a careful examination of the month of 
the largest one, in which I found no evidence of teeth, the armament consist¬ 
ing of nothing more than a sharp jawbone and bony palate. In prying the 
jaws apart I found the maxillary muscles to be surprisingly strong, showing 
