THE CELLULAR BASIS 159 



scription parallels what takes place in the 

 maturation of the human ovum, except that 

 there is no evidence that there are more than 

 two suits of chromosomes, one of which is ma- 

 ternal and the other paternal. 



To carry out this comparison in the case of 

 the maturation of the human sperm where 

 there are only 47 chromosomes it is necessary 

 to take another pack and discard an additional 

 card, say the queen of clubs ; then in the union 

 of corresponding red and black cards into 

 pairs the queen of hearts unites with the queen 

 of spades, but the queen of diamonds remains 

 alone, and when the cards are dealt into two 

 hands as before one hand will contain 24 cards 

 and the other 23. 



If now we complete this comparison by ex- 

 tending it to what takes place in fertilization 

 we must take one hand from each of these 

 deals and put them together into one pack; 

 this pack would contain cards of every de- 

 nomination from ace to queen but there would 

 be varying numbers of red and black cards and 

 a mixture of cards from two distinct packs. 

 In no game of cards do corresponding cards 



