184 Degeneration in the Ostrich 



Cause of Degeneration. 



No attempt has been made to arrive at the cause of the degenerative 

 processes which have been in progress for such long ages in the ostrich, 

 and seem likely to continue for ages yet to come. The term " degenera- 

 tive influence" has been mainly employed where necessity arose for 

 appealing to some agency, as being altogether indifferent in its signifi- 

 cance. The fact is we are altogether ignorant of the means by which, 

 under ordinary conditions, changes can be effected in the germ plasm 

 and become manifest in the soma, but a few considerations cognate to 

 the matter may be noted. 



In the first place, whatever the cause may be, there need be no ques- 

 tion that it is an altogether internal or intrinsic one as contrasted with 

 one environmental or extrinsic. The same changes are going on through- 

 out the continent, with all its varied geographical and climatic conditions; 

 the sequences followed and the stages reached are approximately the 

 same everywhere ; there is an entire absence of anything aberrant or 

 fortuitous. All these point to something common to the race, and 

 altogether beyond environmental agencies. The influence is so slowly 

 acting, and has continued for so many ages and ages, as to call for an 

 aloofness, an independence of external vicissitudes. Only something 

 inherent within the organism itself and beyond all varying somatic 

 responses could meet demands so continuous and consistent. The germ 

 plasm alone satisfies the call for racial continuity. With our present-day 

 conception of its continuity, the germ plasm supplies* us with a vehicle 

 which admits of a uniform influence being carried on uninterruptedly for 

 countless generations. In fact degeneration in the ostrich seems to be 

 as much a part of the race as does the germ plasm itself, and the one 

 may well be part and parcel of the other. No evidence whatever is 

 afforded that the changes are instituted because of any direct bearing on 

 the welfare of the bird, or to meet any outward set of conditions ; any 

 adaptive relationship arising is wholly incidental. • The direction of the 

 changes comes entirely from within, there being the greatest improbability 

 of any guiding trend from natural selection. 



One of the most impressive features of the degenerative changes of 

 the ostrich is the determinate nature of the influence at work, the 

 absence of anything fortuitous, as if it were carried on generation after 

 generation according to some definite, pre-determined plan. The ordinal 

 succession of losses of the coverts and remiges, the gradual loss of the 

 down, the regular sequence of losses of the digits of the wing and foot 



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