64 Professor Halford. 



gramme, which kills within eight or twelve hours all 

 the other non-vaccinated rabbits. 



" Finally, certain substances, such as hypochlorite of 

 lime and chloride of lime, ^uithout mixing with venom, 

 injected in small quantities for four or five consecutive 

 days under the skin of rabbits, produce without fail 

 the refractory state. The animals thus treated can, 

 after six days, resist a mortal dose. 



"Thus I have given immunity to rabbits, guinea- 

 pigs, and to one dog. Operating with precaution, and 

 weighing regularly the animals so as to let those who 

 fall in condition rest, it is easy to succeed in making 

 them support truly colossal quantities of pure venom. 

 I have rabbits, and have had them for the last eight 

 months, which have each received from 30 to 35 milli- 

 grammes of cobra poison, and are now in perfect 

 health." 



Properties of the Blood Serum of Animals which 

 have received Immunity. 



" The serum of animals which have received im 

 munity against the venom by either of the preceding 

 methods, possesses similar properties to those which 

 MM. Behring and Kitasato, Roux and Vaillard, have 

 established for the serum of animals against the poisons 

 of tetanus and diphtheria. 



" The serum of a rabbit which has been rendered 

 proof against the venom of the cobra or the viper, 

 acts exactly in the same way with the venoms of the 

 Australian snakes" 



