206 SYMBIOSIS 



of the head noted by Darwin in Variation, as the result of 

 long-continued over-feeding in the case of the pig, bulldog, etc. 

 abundant and rich food supplied during generations tending 

 to make the head broader and shorter (p. 89). 



We may say that the phenomena are connected with indis- 

 criminate feeding of one kind or another. Such feeding produces 

 antitheses until, by way of compensations and of correlations, 

 atrophies in certain bone structures arise simultaneously with 

 morbid increases, or hypertrophies in others. Since the develop- 

 ment of the senses depends upon exercise, and since the finer 

 usage of the organ of smell is surrendered with a transition from 

 symbiotic cross-feeding to indiscriminate non-symbiotic feeding, 

 it is only too likely that a resulting diminution in the power of 

 the olfactory organ leads to some under-nourishment of the 

 organ and eventually to an atrophy in the nasal bones. 



Dr. Larger has no difficulty in refuting the view expressed 

 by many " Biologistes-normaux " to the effect that hypertrophied 

 parts are merely a normal defence of the organism. Of course 

 if it comes to a combat, he says : 



N'importe quel animal, il fait fleche de tout bois, comme on dit : il 

 se bat unguibus et rostro. . . C'est assurement cette impuissance complete 

 a leur attribuer un role quelconque qui a determine les zoologistes aux- 

 quels repugne 1'idee meme d'un organe inutile, et qui ne veulent pas 

 admettre qu'un animal, normal a leurs yeux, puisse etre teratologique en 

 quoi que ce soit. C'est, dis-je, evidemment cette idee fausse qui les a 

 determines a se rejeter sur celle d'une arme de combat. 



The inadequacy of the Darwinian concept of " utility " 

 lacking as it does, due standardisation is thus again brought 

 home to us. Usefulness quoad mere expediency is not the same 

 as usefulness quoad advancement of life generally. 



In speaking of the astounding development of the incisors 

 in the Proboscidea, Dr. Larger further says : 



Sans doute, que dans le principe, le role de ces dents devait etre necess- 

 airement fonctionnel, et ce n'est que dans la suite, que ce meme role, cette 

 fonctionnel a du se perdre, par une cause pathologique. Aussi bien, cette 

 degradation insensible des " Defenses " decoule-t-elle de 1'histoire meme 

 du Rameau des Proboscidiens. Nous assistons ainsi aux phases succes- 

 sives de la Centre-evolution la'plus interessante, Centre -Evolution s'exerfant 

 sur un organe special tel que la dent. , 



II est incontestable, en effet, que chez Moeritherium Lyonsi (Eocene 

 moyen et superieur) les deux incisives externes du haut et du bas (qui 

 deviendront plus tard les defenses) se touchant par leurs pointes, etaient 



