THE CELLULAR BASIS 165 



fling of these cards corresponding cards of the 

 red and the black suits are temporarily stuck 

 together so that the ace of diamonds is united 

 with the ace of clubs, the queen of hearts with 

 the queen of spades, etc., thus forming 24 red- 

 black pairs of the same denominations. If 

 these cards are then dealt into two hands, one 

 card of each pair going to one hand and the 

 other to the other hand, we will have two 

 cards of each denomination in each hand, but 

 if the cards are dealt indiscriminately some of 

 them will be red and some black. This de- 

 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 



