144 The Science of Life. 



The applications of this, in one sense, very satisfac- 

 tory theory to the phenomena of atavism, and reap- 

 pearance of similar characters at similar times, do not 

 concern us in this general survey. Its great defect, 

 obvious, of course, to its author, was its entirely hypo- 

 thetical character. No one has ever observed any 

 gemmules; their migration, collection, and development 

 are equally hypothetical. 



Another theory, that of Jaeger, is somewhat difficult 

 to summarize, partly because of its technical character, 

 partly because the author does not appear to have been 

 quite consistent. The main points, under the present 

 section, are the following : 



(1) Each organ and tissue contains, along with the 

 molecules of its albumen, a specific " scent-and-flavour- 

 stuff". 



(2) In hunger and similar experience the albumen 

 liberates the " stuffs", which then penetrate through 

 the body as fatty acids, ethers, &c. 



(3) These are particularly attracted to the reproduc- 

 tive cells, and may be said to specialize the germinal 

 protoplasm. 



From experiments on the transfusion of blood, Galton 

 was led to conclude that "the doctrine of pangenesis, 

 pure and simple, is incorrect". But he did more than 

 urge serious objections against Darwin's theory; he for- 

 mulated one of his own, to which subsequent investiga- 

 tors have rarely done sufficient justice. The more im- 

 portant part of Galton's theory will be discussed in its 

 proper place; it is not included in the series of pangene- 

 tic hypotheses. Galton is, in fact, one of the numerous 

 biologists who have suggested the continuity of the 

 germinal protoplasm. He is included at this stage, 

 however, because he admitted as a subsidiary hypothesis 

 a limited amount of pangenesis. To account for those 

 cases which suggest that characters acquired by the 

 individual parent are "faintly heritable", Galton sup- 

 posed that "each cell may throw off a few germs that 

 find their way into the circulation, and have thereby a 

 chance of occasionally finding their way to the sexual 

 elements, and of becoming naturalized among them ". 



