218 SOME EXPERIMENTS WITH THE 
would not receive their normal amount of oxygen. In all my experiments the heart con- 
tinued to beat regularly long after respiration had ceased, so that this cannot have been 
the cause of death. 
4. If the poison acted upon the blood in such a way as to destroy its power to carry 
oxygen—as Cunningham * says is true of cobra yenom—or, 
5, if the poison caused the formation of clots in the veins, thus stopping the flow 
of blood—as Martin tells us the yenom of the Australian black snake does—in either 
case the effect would be the same as if the action of the lungs were to cease. 
The sudden death of my Gila Monster prevented me from testing these possible 
causes of asphyxiation from its poison, but I shall not be surprised if it be found that in 
one or both of them exists the explanation of the phenomena exhibited. 
But perhaps I should limit this statement somewhat, for Mitchell and Reichert state 
very positively of their experiments that death was occasioned by the action of the 
poison upon the heart. Here is an apparent contradiction of my results, and by the 
highest American authority upon reptile poisons; but the seeming contradiction disap- 
pears, perhaps, when we recall that Dr. Mitchell’s Gila Monster saliva was less dilute 
than mine, and that it is known of some serpent poisons that “ with higher concentration 
of yenom the heart is the more rapidly affected, but the continuous operation of the 
poison in small concentration more quickly affects the respiratory ” system. 
IV. SOME CAUSES OF DIVERSITY OF OPINION. 
We have now reached our last question: Why has the bite of the Gila Monster so 
often been considered harmless ? 
Several reasons must, I think, already have suggested themselves. Dr. Shufeldt, it 
will be remembered, was severely bitten on the thumb, and concluded that the bite of the 
Gila Monster is no more poisonous than that of other angry animals; for example, a cat. 
But Dr. Shufeldt expressly states that the wound was made by the upper teeth pene- 
trating to the bone, and we have already seen that the saliva of the upper jaw is harmless 
at all times, the venom being confined to the lower jaw. So it well may be that Dr. 
Shufeldt owes his life to the circumstance that the injury to his thumb was inflicted by 
the upper instead of the lower teeth of the Monster. 
This same fact will account for the experiences of other authors who have thought 
the bite of this reptile harmless, but there are other reasons for the occasional failure of 
the Heloderma to inflict a deadly wound. The teeth, although sharp and long, are very 
weakly fastened to the jaws, and often so many of them haye been broken out that the 
*Cunningham, Sez. Wem. Med. Officers Army India, LX, 1895, pp. 1-54. 
+ It would be interesting to know why the teeth of the upper jaw are grooved. 
