92 NATURAL SCIENCE [August 



language, and please observe the use of the word " degeneration " 

 is thus avoided. 



The structural changes in the gerontic stage of the individual 

 are repeated with sufficient accuracy in the adult, and often even in 

 the younger stages of types that occur in the decline of the evolu- 

 tion of a phylum, so that one is forced to consider seriously whether 

 they may not have been inherited from types that occur at the acme 

 of the same group. The fact that these changes occur first in the 

 individual during the gerontic stage does not necessarily imply that 

 they first make their appearance after the reproductive period. No 

 gerontic limit is known to the reproductive time in the lower 

 animals, and it may well be that the continual recurrence of 

 gerontic stages in individuals during the epacme of groups may 

 lead to their finally becoming fixed tendencies of the stock or 

 hereditary in the phylum, and thus established as one of the 

 factors that occasion the retrogression or decline of groups. The 

 decline may also be considered as occasioned by changes in the 

 surroundings from favourable, as they must have been during the 

 progression up to acmatic time, to unfavourable during the succeed- 

 ing declining period in evolution. Still a third supposition is also 

 possible, viz., that the type, like the individual, has only a limited 

 store of vitality, and that both must progress and retrogress, complete 

 a cycle and finally die out, in obedience to the same law. 



All of these views can be well supported, but, whatever may be 

 the true explanation, it is obvious that there are plenty of declining 

 types, which, in their full-grown and even in their adolescent 

 stages, correlate in characters and structures with the characters 

 and structures that one first finds in the transient old age or 

 gerontic stages of acmatic forms of the same type. These can, 

 therefore, be truthfully and accurately described as phylogerontic 

 or old in the phylum. 



The position of man is at the extreme end of a series of con- 

 verging lines in his own stock. This is also indicated by his 

 structure and development which is phylogerontic, and it is 

 therefore of the highest importance for him to avoid all move- 

 ments tending to the increase of his natural and possibly inherent 

 tendencies towards retrogression. The approximation of the sexes 

 in habits of body or mind is therefore to be avoided, as possibly 

 leading to convergence of the progressive characters non-existin- 

 between the sexes and the inauguration of retrogressive evolution. 



It is hoped that no pretence of being able to solve problems 

 requiring such vast knowledge and many-sided considerations will 

 be attributed to this article, which has been intended simply to call 

 attention to the scientific side of the question. It seems obvious 

 that the time has come when thoughtful men and women should be 



