THE CHROMOSOMES OF THE CHICK SOMA

¹ THE ROCKEFELLER INSTITUTE FOR MEDICAL RESEARCH AND THE ZOÖLOGICAL LABORATORY, UNIVERSITY OF PENNSYLVANIA

1. The chromosome number in the somatic cells of he chick is about 35 or 36.

2. No characteristic differences between the number, the sizes, the morphology or the behavior of the chromosomes in comparison either with each other or with the cells of the gonads have been noted.

3. In view of the entire similarity of the somatic and germinal mitotic behavior and in consideration of the complete inability of highly specialized cells to regenerate other than cells similar to themselves it is tentatively suggested as a basis for future discussion that the somatic chromosomes, as far at least as their genetic function is concerned, have either become functionless or their cytoplasmic environment is incapable of reacting to the possibilities presumably carried by them.