CONFORMITY TO TYPE 257 



memoir. I account for all varieties of the gemmules being found 

 in all parts of the body by the above-mentioned segmentations 

 being never clean and precise. 



"Hence it follows that each segmentation must contain stray 

 and alien gemmules, and I suppose that many of these become 

 eutangled and find lodgment in the tissue developed out of each 

 segmentation.) " 



Having thus enclosed all of the hereditary matter in 

 the germinal cell from a part of which the new being 

 develops, and the "residue" of which, by multiplication 

 of its units, lays the foundation for the next generation, 

 Galton saw that it would be inconsistent that variations 

 should occur among descendants. He says: 



"It is supposed "that the structure of an animal changes when 

 he is placed under changed conditions; that his offspring in- 

 herit some of his change; and that they vary still further on 

 their own account and in the same direction, and so on through 

 successive generations until a notable change in the congenital 

 characteristics of the race has been effected. Hence it is concluded 

 that a change in the personal structure has reacted on the sexual 

 elements." "For my part I object to so general a conclusion. 

 . . . We might almost reserve our belief that the structural 

 cells can react on the sexual elements at all and we may be con- 

 fident that they do so in a very fiant degree; in other words, 

 that acquired modifications are barely, if at all, inherited, in the 

 correct sense of that word." "If they were not heritable, then a 

 certain group of cases would vanish, and we should be absolved 

 from all further trouble about them; but if they exist, in however 

 faint a degree, a complete theory of heredity must account for 

 them." "I propose ... to accept the supposition of their 

 being faintly heritable and to account for them by a modification 

 of pangenesis." "Each cell may be supposed to throw off a few 

 germs that find their way into the circulation, and thereby to 

 acquire a chance of occasionally finding their way to the sexual 

 elements and of becoming naturalized among them." 



The occasional non-appearance in the offspring of 

 qualities for which the parents have been exceptionally 

 remarkable, and which may reappear in the third genera- 

 tion, is attributed by Galton to the particular gemmules 

 from which these qualities arise having become tempora- 

 rily exhausted in the stirp, in which they again appear 

 by multiplication during the preparation of succeeding 

 generations. 



The doctrine of gemmules formed the foundation 

 of another theory of inheritance suggested by Brooks. 



17 



