IO22 THE AMERICAN NATURALIST. 
result of the defibrinating process. The animals suffered no 
ill effects from the operation. Twenty-five cubic centimeters 
of human blood was injected, into a ten- year-old chimpanzee. 
For two days the urine was tested and showed no signs of 
hemoglobin or albumen. The injected blood apparently pro- 
duced no effects whatever. It has been shown by successful 
blood transfusion experiments that the blood of such widely 
separated races as the negro and white is physiologically 
equivalent. 
These blood comparisons, as well as the embryological 
researches of Selenka, justify placing man and the anthropoid : 
apes together in the same family, or at least in the same 
suborder, rather than isolating man in a suborder of pri- 
mates, coórdinate with the suborders of the platyrhines and 
catarrhines. 
The chemical similarity of the blood of morphologically simi- 
lar animals is not surprising. The thing inherited through the 
ovum and spermatozoón is not “innere Impulse," * Iden," or 
“ Entwickelungsmóglichkeiten," but a certain definite chem- 
ical composition, of the molecule. Development, form, and 
the nature of the metabolic processes are as closely dependent 
upon the chemical composition of the molecule as any chemical - 
reaction is dependent upon the chemical composition of the 
reagent causing it. Similarity in the chemical composition of 
blood is but one factor in the chemical similarity of closely 
related organisms. The chemical similarity of reproductive 
cells must be regarded as an epitome of all the chemical simi- 
larities of the adults. 
It is well known that the horse and ass, dog and wolf, rabbit 
and hare readily cross. It would be a valuable experiment to 
attempt, by means of artificial fertilization, a cross between the 
rat and mouse, or between the domestic cat and the ocelot. 
The physiological similarity of the blood of either pair of ani- 
mals points toward the possibility of a successful crossing. 
