142 ORGANIC EVOLUTION CONSIDERED 



out the sexual method propagation would, in a short 

 time, cease. 



He states the differences between the methods of 

 reproduction among the Protozoa and Metazoa as 

 follows: "In nearly all cases where a Protozoan mul- 

 tiplies itself by fission, the process begins by a simple 

 division of the nucleus. But when a Metazoan is de- 

 veloped from a germ-cell, although the process like- 

 wise begins by a division of the nucleus, this division 

 is not a simple or direct one; on the contrary, it is 

 inaugurated by a series of processes going on within 

 the nucleus, which are so enormously complex, and 

 withal so beautifully ordered, that to my mind they 

 constitute the most wonderful — if not also the most 

 suggestive — which have ever been revealed by micro- 

 scopical research. It is needless to say that I refer to 

 the phenomena of karyokinesis." * 



Again he says: "Lastly, the only other distinction 

 of a physiologically significant kind between a single 

 cell when it occurs as a Protozoan and when it does 

 so as the unfertilized egg of a Metozoan is, that in 

 the latter case the nucleus discharges from its own 

 substance two minute protoplasmic masses (polar 

 bodies) which are then eliminated from the cell alto- 

 gether. This process . . . appears to be of in- 

 variable occurrence in the case of all egg cells, while 

 nothing resembling it has ever been observed in any 

 of the Protozoa." t 



The Metazoan generally reproduces by means of 

 eggs which must be fertilized by spermatazoa, and 

 when they reproduce by budding this is ultimately 

 due, according to Romanes, to the sexual method. 

 The ovum and the spermatazoa may both be pro- 

 duced by the same or by different individuals. The 

 * Darwin and Alter Darwin, p. 129. + Ibid, p. 114. 



