116 



Professor Thomas R, Fraser 



[March 20, 



Mr. Davis, also of the New Veterinary College, for much valuable 



Following the same plan of research with the three other venoms, 

 it was found "that for rabbits the minimum-lethal dose per kilogramme 

 of the Diamantina venom is 0*015 grm.; of the venom of Sepedon 

 Jisemachates, -0025 grm.; and of the venom of Crotalus, -004 grm.* 

 The Crotalus venom was, in its purity, altogether comparable with the 

 cobra venom; and the determinations, therefore, show that cobra 

 venom is sixteen times more powerful than Crotalus or rattlesnake 

 venom. This venom, as well as the two others, however, much 

 exceed cobra venom in the intensity of their local action. When 

 death is produced by Crotalus venom, the subcutaneous tissues become 



Fig. 1. — Immunisation of a rabbit against 50 times the minimum-lethal dose of 

 cobra venom. The crosses connected by the continuous line represent 

 administrations of venom. The dots connected by the interrupted line 

 represent the weights of the animal. 



extensively infiltrated with a large quantity of blood and of blood- 

 stained serum, the underlying muscles are reduced to an almost 

 pulpy blood-stained substance, and decomposition occurs very soon 

 after death. Similar changes in the subcutaneous tissues, but to a 

 rather less degree, are caused by the Diamantina venom, and in addi- 

 tion, haematuria, or more probably hsemoglobinuria, was invariably 

 produced by lethal and by large non-lethal doses. I mention these 

 circumstances to indicate the perfection of the protection which is 

 produced by the administration of successive gradually increasing 

 doses; for they can be so adjusted that a dose of the Diamantina 



* Diamantina venom, Ig milligramme. 

 Sepedon ha&macliates, 2J „ 



Crotalus Jwrridus, 4 „ 



