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PART IV. 



THE REPRODUCTIVE FUNCTIONS. 



CHAPTER I. 



REPRODUCTION. 



Limits have been assigned to tlic duration of all living 

 beings. The same power to vvbom they owe their creation, 

 their organization, and their endowments, has also subjected 

 them to the inexorable Law of Mortality; and has ordained 

 that the series of actions which characterize the state of life, 

 shall continue for a definite period only, and shall then ter- 

 minate. The very same causes which, at the earlier stages 

 of their existence, promoted their development and growth, 

 and which, at a maturer age, sustained the vigour and ener- 

 gies of the system, produce, by their continued and silent 

 operation, gradual changes in the balance of the functions, 

 and, at a later period, effect the slow demolition of the 

 fabric they had raised, and the successive destruction of the 

 faculties they had originally nurtured and upheld.* With 

 the germs of life, in all organized structures, are conjoined 

 the seeds of decay and of death; and however great may 

 be the powers of their vitality, we know that those powers 

 are finite, and that a time must come when they will be ex- 



• See the article '• Age," in the Cydopxdia of Practical Mcdiciney where 

 I have enlarged on this subject. 



