THEORY OF REPRODUCTION. 215 



CHAPTER XVII. 



THEORY OF REPRODUCTION. 



I. The Essential Fact in Reproduction. — In the foregoing 

 chapters the facts involved in the different forms of reproduction have 

 been analyzed apart, and separately discussed. Male and female 

 organisms have been interpreted as relatively katabolic and anabolic ; 

 the origin of sex, in the individual and in the race, has been traced 

 back to the preponderance of anabolic or katabolic conditions ; the 

 ultimate sex-elements were seen to exhibit the same contrast in its 

 most concentrated expression ; fertilization was regarded as a katabolic 

 stimulus to an anabolic cell, and on the other side, of course, as an 

 anabolic renewal to a katabolic cell, as well as the union of opposed 

 hereditary characteristics. Only by a separation of the problem of 

 "sexual reproduction " into its component problems can the solution 

 be reached. Sexual reproduction is like a complex musical chord in 

 the organic life, combining several elements, all of which, however, 

 admit of the same fundamental analysis. Two problems remain, — 

 the psychical aspect of the process; and the import of that common 

 feature of all reproduction, the separation of part of the parent organ- 

 ism to start a fresh life. The latter forms the subject of the present 

 chapter. 



II. Argument from the Beginnings of Reproduction. — 

 Leconte and others have pointed out that reproduction really begins 

 with the almost mechanical breakage of a unit-mass of living matter, 

 which has grown too large for successful coordination. Reproduction, 

 in fact, begins as rupture. Large cells beginning to die, save their 

 lives by sacrifice. Reproduction is literally a life-saving against the 

 approach of death. Whether it be the almost random rupture of one 

 of the more primitive forms such as Schizogenes, or the overflow and 

 separation of multiple buds as in Arcella, or the dissolution of a few 01 

 the infusorians, an organism which is becoming exhausted saves itseh 

 and multiplies in reproducing. In some cases, reproduction is effected 

 by outflowing processes of the cell, which have gone a little too far. 

 Now, such primitive forms of multiplication, gradually becoming more 

 definite, express a predominant katabolism in the unit-mass. Repro- 

 duction in its simplest forms is associated with a katabolic crisis. 



III. Argument from Cell-Division. — Most unicellular organ- 

 isms reproduce by cell-division; and this is, of course, a precedent of 



