216 THE NATURE AND ORIGIN OF LIFE 



16), 



wire ; and yet you would separate the pile in two parts, 

 of which the reunion would be indispensable to its function* 

 ing. In the same way, when the strange phenomenon of 

 sexual maturation transforms the repro- 

 ductive elements into incomplete cells, it 

 is not by destroying the nucleus of the 

 female and the cytoplasm of the male. 

 At least, things pass otherwise morpho- 

 logically. 



There remains in the ovule or mature 

 16. NATURE female element a body called nucleus, or 

 more accurately female pronucleus (Fig. 

 drowned in a very considerable mass called ovulary 

 cytoplasm. 



In the same way, in the spermatozoid or mature male 

 element there remains, beside the nucleus or male pronucleus, 

 a very small quantity of substance 

 often called male cytoplasm, or sper- 

 mocentre (Fig. 17). Thus maturation 

 is a less simple phenomenon, at 

 least from the morphological side, 

 than would be the separation of one 

 single nucleus and one single cyto- 

 plasm. We have to resign ourselves 

 to the idea that, as with many very 

 important phenomena of biology, 

 maturation is not susceptible of 

 direct optical study because it 

 does not consist in a production or destruction of 

 elements of the cell. There is a nuclear maturation and 

 a cytoplasmic maturation, tha.t is, maturation transforms 

 a complete nucleus into an incomplete pronucleus, male 

 or female, and a complete cytoplasm into an incom- 



Spcrmocentre or Male 

 Cytoplasm 



FIG. 17. A SPERMATOZOID. 



