Multicellular Bodies 365 



But we have seen that although each half cell carries its 

 complete record it cannot act upon that record alone. It has 

 come to the end of its self divisibility atomically, or of its 

 energy ; so that it cannot again divide. But, in experiencing 

 this deprivation, it appears to have gained a new faculty. 

 Before it split up into ultimate units, it had no power to 

 unfold its heredity. It had then a doubled nucleus and 

 doubled centrosome, and when provoked to division, it merely 

 divided into two similar nuclei, each of which took its share 

 of cytoplasm and made one new cell. But never did it divide 

 into more than two cells. Now, however, each half cell has 

 only a half nucleus and there is between these half nuclei 

 a tremendous attraction of affinity. They amalgamate in 

 conjugation of opposite sexes. 



The division which ensues is not the simple division which 

 followed the conjugation of similar cells. It is a precipitate 

 growth in the abnormal cyto-mass of the egg, of the new nu- 

 cleus, so phenomenal that over and over again its substance 

 is halved, in a succession of divisions. The energy developed 

 is incomparably greater than that seen in the division of cells 

 in ordinary growth. It may be surmised to be proportionate 

 to the great chemical unlikeness of the two elements, male 

 and female, which have been preparing in different environ- 

 ment for a long period. In this rush of growth the cells 

 divide in a new way, which engenders the somatic series. 

 Taking first each a full share of all the nucleus they form a 

 "morula" or bunch of cells just as did the protozoan ancestor 

 in whose body the first bead of the nucleus was saved. Now 

 presumably, this activity is first evolved in one of the chro- 

 mosomes, which is thus growing and dividing and controlling 



