194 BACTERIA IN DAILY LIFE 



by eel's blood, or, in other words, to standardise 

 the poisonous principle contained in it, so as to 

 afford a guide to those experimenting on the 

 subject; and it has been asserted that one cubic 

 centimetre, or about twenty drops, injected into 

 the veins of a rabbit weighing four pounds, may 

 be regarded as a fatal dose for such an animal. 

 But many difficulties surround such an attempt 

 to exactly define the degree of toxic action 

 possessed by such a substance, for, in the first 

 place, the blood varies in respect to this property 

 in different eels, whilst it also differs widely in 

 character at different stages of the life of the fish. 

 This seasonable variation in toxic character has 

 been noticed in the case of viper venom, which it 

 will be remembered was shown to be far more 

 lethal in action when collected from snakes in the 

 spring of the year than in the winter months. 



The toxic substance contained in eel serum 

 was originally called by its discoverers, the Mosso 

 brothers, ittio-tossina ; and they record the fact 

 that the blood of rabbits and frogs, which animals 

 had succumbed to its action, did not coagulate 

 after death, whilst, curiously, in the case of dogs 

 ' this abnormal phenomenon was not observed. 



There are various means which may be resorted 

 to for destroying the poisonous principle contained 

 in eel blood, and from a dietetic point of view it 



