IMPOETANCE OF THE REPRODUCTIVE SYSTEM. 389 



li\ tho phenomena observed, and thus finds principles from which many 

 experiences can be derived. This is more than mere experience; it is, 

 so to speak, philosophical experience." JOHANNES MULLEE (1840). 



IF we judge of the importance of the organ-systems of the 

 animal body according to the number and variety of 

 phenomena which they present, and according to the 

 physiological interest connected with them, we must recog- 

 nize as one of the most important and interesting organic 

 systems, the one to the development of which we now, 

 finally, turn ; the system of the reproductive organs. Just 

 as nutrition is the first and most important condition of 

 self-preservation of the organic individual, so by repro- 

 duction alone is the preservation of the kind or species 

 effected, or, rather, the preservation of the long series of 

 generations, which in their genealogical connection form the 

 sum of the organic tribe, or phylum. No organic individual 

 enjoys an eternal life. To each is granted but a short 

 span of time for his individual evolution, a brief, fleeting 

 moment in the long millions of years of the earth's organic 

 history. 



Reproduction in connection with Heredity has, there- 

 fore, long been regarded as, after nutrition, the most 

 important fundamental function of the organism, and it is 

 customary to make this a primary distinction between 

 living bodies and lifeless or inorganic bodies. But this 

 distinction is in reality not so deep and thorough as it at 

 first appears, and as is generally assumed. For, if the 

 nature of the phenomena of reproduction is closely con- 

 sidered, it is soon seen that it may be reduced to a more 

 general quality, that of growth, which belongs to inorganic, 

 as well as to organic bodies. Reproduction is a nutrition 



