1896.] on Immunisation against Serpents' Venom. 113 



of cobra venom. Working with tlie venom of vipers, Kaufmann in 

 1891, and Phisalix and Bertrand in 1893, obtained experimental 

 evidence of tbe possibility of producing a definite, though not high 

 degree of resistance against the toxic effects of this venom. In the 

 following year, Calmette, continuing some earlier observations which 

 had led him to express the opinion that protection against snake 

 venom could not be produced, published evidence confirming the 

 results of previous investigators, but also showing that a higher 

 degree of protection could be secured than they had obtained, for he 

 succeeded in administering to each of several rabbits, within a period 

 of eight months, a total quantity of from 30 to 35 milligrammes of 

 venom. 



In 1894, also, both Phisalix and Bertrand and Calmette obtained 

 evidence of the power of the blood-serum of protected animals to 

 counteract the effects of venom. Calmette at the same time claimed 

 that hypochlorite and chloride of calcium were antidotes of consider- 

 able value ; and in a later publication, he showed that the blood-serum 

 of animals immunised by the administration of venom possesses a 

 certain degree of antidotal efficacy against the toxines of several 



In the case of many of the venoms which I have had the good 

 fortune to obtain, the quantity at my disposal was not sufficient for 

 experimental examination on the plan that seemed desirable, and, 

 besides, the examination of each of them would require several months 

 of work. The venoms that have as yet been used are four in number, 

 those namely of the cobra of India (Naja tripudians), of the Crotalus 

 Tiorridus of America, of a large colubrine snake, probably a species of 

 Diemenia from Queensland, Australia, and of the Sepedcm Jisemachates 

 of Africa. They are, therefore, those of the most deadly of the 

 poisonous serpents of Asia, America, Australia and Africa respec- 

 tively ; and, further, they are representative of the chief differences 

 that occur in the composition and action of venoms, for they are 

 derived from members of the two great groups of the colubrine and 

 viperine serpents. My supply of cobra venom, however, being much 

 larger than that of any of the others, this venom was chiefly used in 

 the experiments. 



An esssential preliminary to exact investigations with active 

 substances must always be the determination of the activity of the 

 substances. The only convenient method for doing this is to define 

 the smallest dose capable of producing death for any given weight of 

 animal — that is, the minimum-lethal dose. The venoms in their natural 

 liquid state are unstable, and they are also inconstant in activity, 

 mainly because of variations in the quantity of the water which they 

 contain. Dried venoms have therefore been used in all the experi- 

 ments. The cobra venom has, however, nearly always been received 

 in the form of a dry solid ; but when this was not so, it has been 

 dried in vacuo over sulphuric acid. 



Experiments were made with it on several animals — as the frog. 



Vol. XV. (No. 90.) I 



