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sation in dififerent parts of the cell nucleus, no two of which can be 

 assumed to be identical. In view of this manner of the formation of 

 chromosomes it seems absurd to assume that the separation of an 

 individual chromosome by one plane could be qualitative, while the 

 separation by another plane was quantitative. There seems to be no 

 escape from the general proposition that whether a chromosome is 

 divided longitudinally or transversely, the resulting halves necessarily 

 differ from each other in a qualitative manner. Each minute particle 

 which goes to make up the chromosome is at one time separated by 

 some distance from the others, and must undergo a slightly different 

 experience and be subjected to slightly ditierent conditions. Every 

 such particle, therefore, according to strict interpretation, must have 

 certain hereditary tendencies which are not possessed by any other, 

 and is therefore qualitatively different from every other particle. It 

 is consequently quite impossible to make a division of the body thus 

 constituted in such a way that one half shall be qualitatively equal 

 to the other half. 



The whole question, therefore, whether a certain division is longi- 

 tudinal or transverse, loses its practical significance, since the theoretical 

 interpretation which has long been placed upon these divisions is 

 shown to be impossible and absurd. Furthermore, there are certain 

 practical difficulties in determining whether, according to the accepted 

 definitions, a certain division is longitudinal or transverse; and these 

 difficulties are by no means small or simple in the majority of cases. 

 In fact, the actual conditions as seen under the microscope, are usually 

 forced into the general scheme, which admits only two kinds of division 

 and defines the meaning of these divisions. On general principles it 

 seems rash to assume that the process of maturation in various ani- 

 mals and plants should be so remarkably uniform that one hard and 

 fast formula could be established for explaining all cases. It is much 

 more reasonable to believe that the process is not one and the same 

 in all species of animals; and the divergent and irreconcilable accounts 

 already published by different authors lend great weight to this 

 view. 



It is only necessary to refer to any recent publication on the 

 subject to find examples of this attempt to force the divergent pro- 

 cesses in different species to fit the same formula. In a paper by 

 M'Clung (Kansas Univ. Quart., Vol. 9, 1900, No. 1, p. 73—100) we find 

 a most striking example of such forced interpretation. In this paper 

 reference is made to a previous publication by myself on the matu- 



