196 / LIONEL TAYLER [September 



proportions preserved between the various qualitative 

 specialisations. 



(c) Eeproduction on this theory commences when full or nearly 

 full development of a structure is reached, when its growth 

 capacity is in excess of its demands ; from this it will follow 

 that the reproductive units will be collected in the repro- 

 ductive organs in the order of their evolution. 



id) A progressively specialising food supply would determine the 

 development and the atrophy of the different reproductive 

 units. 



(e) The later a specialisation was developed either in the history of 

 the species or the individual the less chance of its obtaining 

 a foothold in reproduction, and conversely these must be 

 the first to be eliminated under stress conditions. It will 

 follow from this that the effects of use and disuse, in so far 

 as they are of a somatic nature, will be very little if at 

 all transmitted to the germinal structures, since develop- 

 ment, in so far as the major part of the organism is con- 

 cerned, will be completed early. 



The first advantage of a theory like the preceding is that it has 

 no need for the supposition of any isolated germ structure, use- 

 inheritance being largely negatived by specialisation. The relation 

 of germinal to somatic development is on this theory understandable. 

 It would account for recapitulation in development, not on the ground 

 of a tendency in the organism to repeat certain ancestral characters, 

 but simply as the necessary preparatory specialisations out of which 

 the later ones are built. 1 It would divide all anomalies into — (1) 

 those cases of faulty representation due to the missing of some prior 

 stage in development, as in the case of cretins, where the morpho- 

 logical element is there but the means of developing it is not, or 

 where deficiency of the element itself as possibly happens in the case 

 of mongoloid idiots ; (2) disproportionate representation (quantita- 

 tive anomaly), leading to dichotomy, etc. ; (3) under rare conditions 

 the reappearance of real ancestral characters. 



If therefore the recapitulation theory lias a different meaning from 

 that of ancestral repetition, and if most cases of so-called atavism can 

 be explained on the assumption of incomplete development, if it is 

 further borne in mind that given the power of segmentation then all 

 that is chiefly required is a proportionate representation of germs, 

 then the complexity of the germ plasm, although very great, need not 

 be so inconceivably great as that which involves the representation of 

 a large number of ancestral as well as all living characteristics. 

 Normal sexual reproduction would on this theory be the right 



1 In a limited sense, however, these stages would represent the history of the individual 

 ancestral line. 



