Some of the properties and the amino acid compositions of the histones of calf thymus, calf liver, fowl erythrocytes, and of a protamine-like material isolated from rooster sperm were described.
The amino acid compositions of the histones were rather similar except that no methionine was found in the fowl erythrocyte histone.
In the fowl, histones are found in the somatic chromosomes and protamines are found in the sperm chromosomes. This shows that great variations in chromosome composition can exist in an organism.
Histone is digested by pepsin both when isolated and when in the chromosome.