Again, in animals poisoned by woorara, the blood is invariably black, and frequently so changed as to coagulate with difficulty, and not to become bright on re-exposure to air.
If we compare this effect of woorara with that of the viper, we shall observe a great analogy between them, varying only in intensity. We may further remark, that woorara, like the poison of the viper, may be introduced with impunity into the intestinal canal. We might be led to suppose from its perfect innocuousness when introduced into the stomach, that it became modified, or in a word, digested by the gastric juice, so as to destroy its deleterious properties. To verify this supposition, we caused some woorara to be digested in the gastric juice of a dog, at a temperature of between 38° and 40° of centigrade. After leaving it for forty-eight hours, we introduced it by puncture into the veins of some animals, who died with the before-named symptoms; establishing the fact, that a prolonged contact with the gastric juice in no way modified its deleterious properties. This experiment has been repeated in various ways, and on the separate parts, as well as on the living animal. We made a dog, in whose stomach we had formed a fistulous opening, swallow some fragments of woorara mixed with his food; after a little time we obtained some of his gastric juice, and on analysis found it to resemble in every respect a solution of woorara. Thus we have the singular phenomenon of an animal, carrying in its stomach, harmless to itself, a liquid { 80} which would cause instant death to any others who should be inoculated with it. Not only did the dog which swallowed the poison experience no fatal result from it, but its digestion was not even affected by it; the gastric juice thus mixed retaining all its digestive properties.
These facts prove that the innocuousness of woorara when introduced into the stomach, is not attributable to the action of the gastric juice. The other intestinal liquids, saliva, bile, pancreatic juice, were attended with similar results, none of them producing by contact the least difference in the poisonous effect of woorara.
The explanation of these facts appears to be simply this: there is a want of absorption of the venomous substance through the gastro-intestinal mucous membrane. This can be shown by the following experiment:—Take the fresh gastric mucous membrane of a dog or rabbit, recently killed; adapt it to an endosmometer in such a manner that the mucous surface remains outwards; then plunge the endosmometer containing sweetened water into a watery solution of woorara, and we shall find, after two or three hours, that the endosmosis will be complete. The level will have risen in the endosmometer, and yet the liquid contained in it will shew no trace of the poison, as can be proved by inoculating other animals with it.