MULTIPLE CHROMOSOMES 581 



mosomes, and general conclusions regarding the nature of 

 chromosome organization may properly be drawn from its his- 

 tory. That its condition is indeed not unique is shown by vari- 

 ous approaches to it on the part of certain chromosomes in 

 Phrynotettix, as demonstrated by Wenrich ('16). The great 

 similarity to the euchromosomes is also indicated by the union 

 with the accessory chromosome in multiples, and by its entirely 

 typical nature in the female when paired. 



The mere academic question of indi\iduality is not here im- 

 portant, the practical matter before us is to decide whether the 

 metaphase chromosomes of two cells are individually identical 

 organic members of a series because they were produced by the 

 observed reproduction of a similar series of the parent cell, or 

 w^hether the resemblance is independent of this genetic relation 

 and due to chance association of indifferent materials, or to a 

 reconstituting action of the cell as a whole. It is my belief that 

 the observed act of reproduction, by which the organization of 

 the chromosomes is materially transmitted in each mitosis, 

 together vnth. all facts indicating extensive distribution of given 

 conditions, definiteness of organization, uniformity of behavior 

 and consistency of de\'iation from the normal, are so many 

 clear indications of the individual character of the chromo- 

 somes. Transmutation of form, even to an extreme degree, can 

 not be held as a vaUd argument against a persistent indi\ddu- 

 ality. A consideration of the criteria applied to larger organic 

 aggregates well supports this \dew. Such objects are said to 

 possess individuality when they exhibit a more or less definite 

 unity which is persistent and characterized by peculiarities of 

 form and function. Most clearly defined is this indi\iduality 

 when it may be perpetuated through some form of reproduction 

 to find expression in new units of similar character. The term 

 does not connote unchangeability, and there may be fusions with 

 more or less loss of physical delimitations, followed by separation, 

 even after exchange of substances. The test of individuahty is 

 material continuity, but it does not necessarily involve com- 

 plete or entirely persistent contiguity. An organism may bud 

 off new individuals similar to itself, the substance of its body 



