DISTRIBUTION OF THE CHROMOSOMES 25 



all represented in every chromosome, nothing particular is 

 accomplished by the complex process of cell division in which 

 an exact representative half of every chromosome present in 

 the fertilised ovum is handed on to every cell produced in 

 the building up of the organism. Again, there would seem 

 to be no point in the still more complicated process of 

 reduction which always precedes fertilisation, and which 

 ensures an alternative distribution of whole chromosomes to 

 the germ cells. Both these phenomena are universal among 

 multicellular plants and animals, and are found in many 

 unicellular forms. It is inconceivable that they can be 

 without any significance. Were every character represented 

 in every chromosome there would be no useful function 

 performed, in so far as these characters are concerned, by the 

 complex processes that ensure that a derivative of every 

 part of every chromosome present in the fertilised ovum 

 shall be distributed to every cell forming the body of the 

 individual arising from it, while they equally ensure that 

 whole chromosomes shall be distributed in an alternative 

 manner to every new individual produced. 



Though it would seem that we must dismiss the chromo- 

 some as the bearers of those characters that are common 

 to all the individuals of the race, there is good reason to sup- 

 pose that they may be the bearers of some characters. We 

 shall see later that there are characters that are transmitted 

 in an alternative manner. After we have considered the 

 nature of these characters and the manner in which they 

 pass from parents to offspring, the possible relationship 

 between these phenomena and the manner in which the 

 chromosomes are distributed in the building up of the 

 organism from the fertilised ovum and in the process of 

 reduction and fertilisation, will be dealt with. At present we 

 must see what evidence there is for an hereditary substance 

 being contained in any particular part of the cell, or whether 

 the transmission of the racial characters is not possibly a 

 potentiality of the whole cell. 



Very many observations upon the phenomenon of 



