MISCELLANEOUS NOTES. 297 



bites. In these ways a partial immunity, whiich is hereditary, is establish- 

 ed, becoming lost in time if the animals be removed to countries where 

 cobras do not exist." 



This theory is a plausible one. But there is a stumbling-block. It is 

 not difficult to imagine a mongoose, by reason of his agility and increasing- 

 experience, surviving a number of encounters at the cost of a few scratches 

 which the antidote in his blood has prevented fron having fatal effects. 

 These successive inoculations together with the poison swallowed at times 

 would tend to increase his immunity, so that an elderly individual might 

 take a good deal more killing than a comparative youngster. 



But can this additional immunity acquired from inoculation be trans- 

 mitted to the animal's offspring ? It is the old question of the heritability of 

 accidentally acquired characters, often affirmed but never proved. Possibly 

 the mongoose may eventually afford the evidence that has hitherto been 

 sought in vain. (I offer this suggestion gratis to any advocates of the theory 

 who may be on the look-out for new lines of investigation. It should be 

 simple enough. Start a mongoose stud and inoculate each generation up to 

 the limit : in course of time, if your breed be a good one you should 

 be in a position to supply all the laboratories in the country with anti- 

 venine !) 



It may be that the fact of the immunising factor being an anti-toxin in 

 the blood places it in a different category to other acquired characters, as it 

 would seem possible for the embryo to be inoculated before birth from the 

 anti-toxic element in its mother's blood. If so, it is sure to be a well-known 

 fact, and I have, in the valour of my ignorance, been merely tilting wind 

 mills. I must take my chance of that ! 



If this is not the case, however, and we decline in the absence of satis- 

 factory proof to believe that acquired characters can be inherited, it follows 

 that we are in entire ignorance as to how the mongoose's existing inherited 

 partial immunity originated, though it has doubtless been strengthened in 

 some measure by centuries of natural selection. From this the further con- 

 clusion may be drawn that this inherited immunity probably almost cer- 

 tainly differs in its nature from such additional immunity as the individual 

 animal may acquire from inoculations during its life-time . 



This conclusion is found to be of value when considered in relation to 

 an important fact, which I have not yet mentioned : I mean the fact of 

 the highly specific character of snake venoms which appear to have been 

 established beyond question by the most recent investigations, alike in 

 India, Australia and America, the consequence of which is that an anti- 

 toxin obtained from the poison of the cobra, for instance, is absolutely 

 ineffective as a curative against the poison of krait or daboia — Calmette's 

 original belief to the contrary notwithstanding. 



Hence it is to be deduced that any immunity which the Indian mongoose 

 38 



