218 THE NATURE AND ORIGIN OF LIFE 



maturation begun in the ovules of a sea urchin or star fish. 

 For this he uses different processes, of which the earliest 

 was the temporary immersion of the ovule under maturation 

 in certain saline solutions. After the immersion, the ovule 

 which was we know not how under way of maturing, showed 

 an arrest in the phenomena of maturation begun within it 

 and so found itself a complete cell and consequently capable 

 of developing itself without fecundation by a spermatozoid. 

 Probably, by such experiments, we may some day discover 

 the very nature of phenomena of maturation. 



Nature affords us examples of incomplete maturation. 

 The bee's egg always remains in an intermediate stage 

 between the complete cell formed solely of bipolar elements 

 (Fig. 18, A) and the real female ovule formed solely of 

 female poles (Fig. 18, B). The egg of the bee would be 

 represented by a juxtaposition of bipolar elements and of 

 elements reduced to their female pole. Consequently, 

 such an egg is capable either of developing by itself or of 

 being fecundated by a spermatozoid. 



Fecundation 



Fecundation is the operation in which the spermatozoid, 

 introduced by sexual attraction into the ovule, completes 

 by means of its male poles the female poles of the ovule's 

 elements, which are incomplete. 



While the optical study of mature sexual elements gives 

 us no information about the nature itself of maturation, the 

 observation of fecundation is, on the contrary, full of 

 instruction inasmuch as it shows us with evidence various 

 sexual attractions between corresponding parts of the ele- 

 ments that enter into fusion. Thus the male pronucleus is 

 attracted toward the female pronucleus (Fig. 19) and directs 

 itself toward it by pivoting around the male cytoplasm, 



