TABOO AND GENETICS 21 



markable pure coincidences and a great deal of 

 folk-lore. 



Reproduction in its simplest form is, then, 

 simply the division of one cell into two parts, 

 each of which develops into a replica of the 

 original. Division is also the first stage in 

 reproduction in the most comphcated animal 

 bodies. To get an idea of what takes place in 

 such a division we must remember that a cell 

 consists of three distinct parts : (a) the proto- 

 plasm or cytoplasm, (b) the nucleus, and (c) a 

 small body known as the centrosome which 

 need not be discussed here. 



When a cell division takes place, the nucleus 

 breaks up into a number of thread-like portions 

 which are known as chromosomes. There are 

 supposed to be 24 pairs, or 48, in the human 

 cell. All the evidence indicates that these 

 chromosomes carry the " factors " in inheritance 

 which produces the characters or characteristics 

 of the individual body. 



In mitosis or ordinary cell division, these 

 chromosomes split lengthwise, so that the new 

 cells always have the same number as the 

 original one. When the germ-cells of the male 

 and female make the division which marks the 

 first step in reproduction, however, the process 

 is different. Half the chromatin material passes 

 into each of the two cells formed. This is called 

 maturation, or the maturation division, and the 



