460 Proceedings of Royal Society of Edinburgh. [sess. 
need scarcely be added that the doses of bile thus shown to be 
sufficient represent only minute portions of the bile stored in the 
gall-bladder of a serpent, and that a serpent, therefore, has at its 
disposal enough of bile to prevent injury from venom introduced 
into the stomach in quantities many times greater than the 
minimum-lethal. 
It appeared of interest to examine in a similar manner the bile 
of innocuous serpents and of other animals. 
All serpents, innocuous as well as venomous, exhibit a resistance 
against the toxic action of venoms introduced subcutaneously or 
directly into the circulation, which is not dependent on their being 
cold-blooded animals. Various facts, some of which are anatomi- 
cal, tend to show that the innocuous, equally with the venomous 
serpents, possess poison glands and secrete venom. The former 
are innocuous only in the sense that they are not normally fur- 
nished with weapons of offence in the form of poison fangs. Most 
probably, therefore, the relative protection against the poisonous 
action of venom introduced into the circulation, which is common 
to serpents, is dependent upon an effect produced upon them by 
the venom which they all secrete, although in the case of the 
innocuous serpents only in relatively small quantities. 
Experiments that were made with the bile of the innocuous 
grass snake have confirmed this supposition. When tested in 
rabbits against ’00025 grm. p. kilo, of the venom of the Indian 
cobra, '002, ’0045, and ’0055 grm. p. kilo, were found insufficient 
to prevent death, but ‘0065, ’0075, and ’01 grm. p. kilo, was each 
found to be able to prevent death. The smallest quantity of the 
bile of this innocuous serpent necessary to prevent death is there- 
fore considerably larger than that of the feeblest of the biles of 
venomous serpents, but still is only a small quantity. 
Experiments were also made with the bile of the ox, as repre- 
senting those animals which do not secrete venom or possess any 
protection against venom introduced into the subcutaneous tissues 
or into the circulation, while at the same time they are unaffected 
by venom introduced into the stomach. It was found that when 
mixed with *00025 grm. p. kilo, of the Indian cobra venom, this 
bile failed in rabbits to prevent death in doses of *01 and ’015 
grm. p. kilo., but succeeded in doses of '02, ’03, *04, ’07, and T5 
