2 88 THE GERM-PLASM 



of the two halves of the body. Apparently all possible combina- 

 tions may actually occur. The form of the skull may resemble 

 that of the father, and the face that of the mother ; or the form 

 of the entire head and face may be like the mother's, while the 

 eyes may be similar to the father's in every detail. The son 

 may, like his father, possess a dimple on the chin, although he 

 takes much more closely after his mother as regards the shape of 

 the face and nose. That the combination of parental character- 

 istics may even extend into far greater details, is shown espe- 

 cially by the remarkable amalgamation of the mental qualities 

 of the parents which often occurs. The intellect and practical 

 talent may be inherited from the mother, and strength of will 

 and unselfishness from the father ; and all these qualities may 

 be contained in one skull, the form of which essentially re- 

 sembles that oi one of the parents only. These combinations of 

 mental characteristics of the parents cannot, however, always be 

 definitely analysed, owing in the first instance to the fact that 

 they are not always sharply contrasted in the parents, but more 

 frequently are only different in degree. We may, however, at 

 any rate consider it certain that l/ie brain rarely resembles that 

 of one parent only in all its parts and as regards tlie most mi- 

 nute details of its structure ; it usually, on the contrary, exhibits 

 a combination or alternation between that of the two parents, 

 and this combination is of the most varied kind. 



In connection with this statement it may be mentioned that 

 no part of the human body is so important as the brain in the 

 stmggle for existence, and its importance extends even to the 

 minutest details ; its parts must therefore be subjected to in- 

 cessant processes of selection. In other words, the number of 

 homodynamous determinants in the various parts of the brain 

 must be extremely different in the individual, and must vary 

 extremely in different individuals. 



These statements with regard to the struggle of the individual 

 characters may perhaps be objected to on the ground tliat tliey 

 contradict the suppositions with wliich we started. It may he 

 contended that an alternation of paternal and maternal hereditary 

 parts is rendered possible on the basis of my theory, because 

 the transmission of a paternal character implies that the whole 

 dominant group of idants of the father passed into the germ- 

 plasm of the child at the reducing division, and the transmission 

 of a maternal character necessitates the presence of the whole 



