114 The Field Naturalist's Quarterly May 



seeking, in the case of snake-bite — to discover something 

 which, on injection into the system, will at once confer 

 immunity to the venom, without having to wait for that 

 something to be elaborated in the tissues themselves. A 

 substance having this power is called a specific anti-sub- 

 stance or antitoxin — that is, something which will antag- 

 onise in some way a poison or toxin. There are many 

 methods of preparing these anti- substances which do not 

 concern us here, the great practical point being that they 

 are found in the serum of the blood of animals which have 

 had the disease in question, and that this serum, on being 

 injected into another susceptible animal, in many cases 

 protects the latter from infection for a certain time, or 

 antagonises the poison already in the system if it is in- 

 jected during an attack of that special disease. The great 

 distinction between the diseases in which this method of 

 treatment is so successful and the case of snake-bite is, 

 that the former are due to specific micro-organisms from 

 which an antitoxin can be obtained, whilst snake-bite is 

 due to a chemical poison secreted by the venom -gland. 

 Still, in both cases, artificial immunity can be conferred in 

 some instances, and it is undoubtedly only a matter of 

 time for the discovery of more exact methods of applica- 

 tion in order to achieve still greater success. If the venom 

 of snakes were the same in all species the problem would 

 soon be solved, but this is by no means the case, and as 

 an antitoxin only antagonises a particular toxin, it is there- 

 fore necessary to obtain separate antitoxins for different 

 venomous bites, or to discover some method by which the 

 various antitoxins can be combined. 



Having thus briefly explained what the idea of immunity 

 involves, we may next consider the special case of the 

 Mongoose. 



VIII. Is the Mongoose immune to Snake-Bite ? 



The various species of Mongoose belong to the order 

 Carnivora, family Viverridae, sub-family Herpestinae, there 

 being over twenty species of the Mongoose or Herpestes. 



