1 - 894 - 5 .] Antivenene and Serpents Blood-Serum. 471 
One of tlie kittens, when fifty-seven days old, and when the 
mother had last received a dose equivalent to thirty times the 
minimum-lethal if given subcutaneously, received, by subcutaneous 
injection, twice the minimum-lethal dose of cobra venom ; and only 
slight symptoms, consisting chiefly of drowsiness and loss of 
appetite, were produced, from which the kitten completely recovered 
in a few hours. 
The second kitten, when sixty-nine days old, received, also by sub- 
cutaneous injection, thrice the minimum-lethal dose ; but the protec- 
tion produced through the mother’s milk was insufficient to antagonise 
this large dose of venom, and death followed the administration. 
Evidence in favour of the production of protection by stomach 
administration, as well as of the toxic feebleness of venom when 
given by this channel, has been obtained with white rats also. Single 
doses, corresponding to 10, 20, 40, 200, 300, 600, and 1000 times 
the minimum-lethal if given subcutaneously, were given by stomach 
administration to each of seven different white rats. Sleepiness 
and loss of appetite, lasting for a day or two, were the only effects 
produced even by the larger of these enormous quantities, and all 
the animals entirely recovered. 
A further experiment was made on the white rat which had 
received 1000 times the minimum-lethal dose. Seven days after this 
dose had been administered, and when the animal was apparently in 
good health, twice the minimum-lethal dose was injected under the 
skin. Distinct though not serious toxic symptoms were produced, 
consisting of sleepiness, anorexia, and increase of salivary and 
bronchial secretion ; but in less than twenty-four hours these 
symptoms had disappeared, and the animal was soon afterwards in 
a perfectly normal state. 
It 'would, therefore, appear that although serpents’ venom, even 
in enormous quantities, fails 'to produce any toxic effects when 
introduced into the stomach, it still confers upon the animal a 
certain and not inconsiderable degree of resistance against the toxic 
effects of subsequent lethal doses of venom. That it does so by 
causing an antidotal substance to be present in the blood is also 
manifest from the result of the experiment on the kitten, which 
had been fed with milk derived from a parent receiving venom by 
the stomach. 
