38o 



THE WONDER OF LIFE 



cells of the following generation'. Thus the parent is 

 rather the trustee of the germ-plasm than the producer of 

 the child. In a new sense, the child is a ' chip of the old 

 block '. 



A third wonder is the extraordinary process of matur- 

 ation or ' reducing division '. The details are diverse and 

 difficult, but the net result of the process may be simply 



Fig. 60. — Part of a dividing cell, a Eadiolarian, showing the chromo- 

 somes in two groups, a, the cytoplasm ; c, the ohiomosomea ; 

 B,r, differentiations in the cytoplasm. {After Haeoker.) 



stated. In each cell in the body of an organism there is 

 ■normally a nucleus or kernel, and within the nucleus a 

 definite number of readily stainable rods, or loops, or 

 granules, called chromosomes. Each kind of hving creature 

 has a particular number, thus there are twenty-four in man, 

 mouse, and hly ; sixteen in ox, guinea-pig, and onion ; 

 twelve in the grasshopper ; two ia one of the threadworms, 

 and so on. There is no doubt that these chromosomes are 

 very important, and most biologists regard them as the 



