112 Professor Thomas B, Fraser [March 20, 



and by larger quantities from Sir William Mackinnon, Director- 

 General of the Army Medical Department, and especially from 

 Surgeon-Colonel Cunningham, of Calcutta, who for many years has 

 been engaged with much success in the study of venoms and their 

 antidotes. Within the last few months, and subsequently to the 

 publication of some of the experimental results which had by this 

 time been obtained, the India Office has also placed at my disposal 

 a considerable quantity of venom, which had been collected by 

 Dr. Hankin, of Agra, at the request of Dr. Cleghoorn, Surgeon- 

 General with the Government of India. 



But, besides these specimens of the venom of the cobra of India, 

 I have also been fortunate in obtaining specimens of venoms from 

 other parts of the world. 



From America, Dr. Weir Mitchell, of Philadelphia — whose work 

 on the chemistry and physiology of serpents' venom constitutes the 

 great advance of the century on the venom of viperine serpents — has 

 supplied me with the venom of three species of rattlesnakes, viz. 

 Crotalus horridiis, C. aclamanteus, and C. durrisus, and also with a 

 specimen of the venom of the Copper Head [Trigonoceplialus contor- 

 trix). 



From Australia, Dr. Thomas Bancroft, of Brisbane, has at various 

 times sent specimens of the venoms of the black snake (PseiidecMs 

 porphyriacus\ the brown snake (Diemenia sujperciliosa), and of a 

 large unidentified snake of the Diamantina district of Queensland 

 (probably a new species of Diemenia). 



From Africa, the kindness of Mr. Andrew Smith, a distinguished 

 naturalist of Cape Town, of Dr. Brook, of the Orange Free State, 

 and of Dr. John Murray and Mr. Van Putten, of Cape Colony, has 

 placed at my disposal small quantities of the venom of the puff adder 

 (Vifera arietans), the night adder (Aspidelaps luhricus), the yellow 

 cobra {Naja liaie\ and the " Ring Hals Slang " or " Einkas " 

 (Sepedon Jisemacliates). 



In the meantime, however, the results of experiments on the 

 inoculation of the toxines of diseases, as well as of proteid toxines of 

 vegetable origin, had suggested to several observers that serpents' 

 venom, because of its chemical analogies with several of these sub- 

 stances, might possibly be found capable, like them, of producing 

 immunity against the effects of poisonous doses ; and further impor- 

 tant evidence has thus been obtained in favour of the reality of the 

 protection to which I have referred. 



Sew^all, in 1886, undertook an investigation with the object of 

 determining if immunity against the fatal effects of rattlesnake venom 

 could be produced by the inoculation of repeated doses, each too small 

 to produce ill-efiects. The experiments were made on pigeons, and 

 he succeeded in proving that immunity could be secured to the extent, 

 at least, of protection against seven times the minimum-lethal dose. 

 Kanthack made a similar series of experiments in 1891, which allowed 

 him to conclude that rabbits may be accustomed to resist lethal doses 



