56 LIFE OF ELIE METCHNIKOFF 



enough to work ; in order to recover quickly, he went 

 to Cava, a pretty little place, renowned for its salu- 

 brious climate. 



There he met Bakounine again, and they saw a 

 good deal of each other in a friendly way. Bakou- 

 nine nicknamed him " Mamma " because of his almost 

 maternal attentions, a nickname which, for the same 

 reason, was given him later, quite independently, by 

 other intimates. Yet, though their relations were 

 cordial and even affectionate, there was not really 

 much in common between the two. Elie thought 

 Bakounine's ideas superficial, and disliked his sectarian 

 mentality ; they ultimately drifted apart. 



His health having gradually recovered owing to the 

 rest, he returned to Naples in the autumn, after the 

 epidemic had abated, and at last resumed his work. 



Whilst studying the history of the development of 

 Cephalopoda he found that they had embryonic 

 layers similar to those of Vertebrates ; this was the 

 first time that the fact was established. It was ex- 

 tremely important, for it constituted a concrete and 

 indisputable proof of the existence of a genetic 

 connection between inferior and superior animals. 

 Metchnikoff chose this subject for his thesis, and, 

 having completed his researches, he returned to 

 Russia in 1867. 



By this time he had made great use of his three 

 years' stay abroad. Though he had not showed 

 himself a docile pupil, yet he had become initiated 

 into the organisation of scientific work in Germany ; 

 he had carried out independent researches and had 

 been able to choose with full knowledge the future 

 path of investigations which he was to pursue for 

 many years in the field of Comparative Embryology. 



