1898] A THEORY OF RETROGRESSION 405 



reproduced exactly in the ontogeny, and then the latter would be as 

 elaborate, and almost as lengthy as regards time, as the former. 

 Moreover, the prototypes of the phylogeny could not exist in the 

 enormously changed environment of the ontogeny. How, for in- 

 stance, could a gill-breathing animal, or any of the higher forms 

 which intervene between them and man, exist in the uterus, in 

 which alone can exist those dim representations of the phylogeny 

 that constitute man's ontogeny ? 



It is this great change of environment, this close protection of 

 the individual in the uterus and afterwards, which has rendered 

 possible the evolution of man and the other higher animals. Oppor- 

 tunity has thus been afforded for retrogression to plane away in- 

 numerable characters which had become useless. The ontogeny has 

 thereby been straightened, shortened, and simplified, and the evolu- 

 tion of new characters, useful in the new environment, has become 

 possible. Thus, for instance, have been rendered possible the higher 

 characters of man, for even after birth he is closely protected, and, 

 therefore, even in that portion of the ontogeny which intervenes 

 between the infant and the adult has there been much retrogression. 

 Consider how feeble and helpless is the infant after birth ; but its 

 prototypes of the phylogeny fought for their own existences. The 

 infant can digest scarcely anything but milk, and its jaws are very 

 feeble. Its prototype must have had much wider powers of digestion. 

 Perhaps more remarkable than anything else is the retrogression of 

 instinct in man. I have dealt at length with this question else- 

 where, and have not space for it here ; but consider how helpless 

 is the infant at birth, how extremely incapable, as compared to 

 young insects, for instance, of adapting itself, of its own initiative, to 

 the environment. Later on it acquires all kinds of knowledge and 

 ways of thinking and acting, which serve as a superior substitute 

 for instinct. But meanwhile the mother's protection, which has 

 rendered possible this acquirement, has rendered useless also the 

 instincts of its prototypes, which have therefore lapsed. Hence the 

 retrogression of instinct in man. By it his mental ontogeny is 

 shortened and simplified, just as by the retrogression of bodily parts 

 his physical ontogeny is shortened. 



In the foregoing I have spoken of characters lapsing in orderly 

 succession, the last first, the earlier later. But it seems to me 

 probable that earlier characters may sometimes lapse before the 

 later. This may happen when some parts of the phylogeny, and 

 consequently of the ontogeny, are not direct, but form a loop, so to 

 speak. The omission of the loop would straighten, and therefore 

 shorten, the ontogeny, and considering how condensed is the latter, 

 I believe this must often occur. G. AKCHDALL REIT). 



9 Victoria Road South. Southsea. 



