VIII.] SUPPOSED TRANSMISSION OF MUTIIATIONS. 449 



grandparents. But this certainly does not imply that the results 

 are due to chance : no one has the right to doubt that everything 

 is brought about by the operation of certain laws, and that, 

 with the fertilization of the ^gg^ the shape of the nose of the 

 future child has been determined. The co-operation of the two 

 tendencies of development contained in the two conjugating 

 germ-cells produces of necessity a certain form of nose. The 

 observed facts enable us to know something of the laws under 

 which such events take place. Thus, for instance, among a 

 large number of children of the same parents some will always 

 have the form of the nose of the mother or of the mother's 

 family; others will have the nose of the father's family, and 

 so on. 



If we apply this argument to the supposed transmission of 

 mutilations, such transmission, if possible at all, must occur a 

 certain number of times in a certain number of cases : it must 

 occur more readily when both parents are mutilated in the 

 same way, or when the mutilation has been repeated in many 

 generations, etc. It is extremely improbable that it would 

 suddenly occur in a case where it was least expected, while it 

 did not occur in 900 cases of the most favourable kind. Those 

 who recognise in the doubtful cases of transmission of a single 

 mutilation present in only one of the parents, proofs of the 

 existence of the disputed operation of heredity, quite forget 

 that the transmission presupposes a very marvellous and ex- 

 tremely complex apparatus which if present at all ought, under 

 certain conditions, to become manifest regularly, and not only 

 in extremely exceptional cases. Nature does not create com- 

 plex mechanisms in order to leave them unused : they exist 

 by use and for use. We can readily imagine how complex 

 the apparatus for the transmission of mutilations or acquired 

 characters generally must be, as I have--tried to show in another 

 place. The transmission of a scar to the offspring e. g. presup- 

 poses first of all that each mechanical alteration of the body 

 {soma) produces an alteration in the germ-cells : this alteration 

 cannot consist in mere differences of nutrition, only affecting 

 an increased or decreased growth of the cells : it must be of 

 such a kind that the molecular structure of the germ-plasm 

 would be changed. But such a change could not in the least 

 resemble that which occurred at the periphery of the body in 



