Dec., 1903.] Transmission of Acquired Characters. 
29 
Obviousl}^ selection of favorable variations is the onh- explana- 
tion here. If, then, we must assume that, for instance, the im- 
mense jaws with the corresponding muscles of the termite soldier 
are produced bj' selection, whj^ must we assume a different cause 
in the case of the antlers of the stag ? When all evidence is 
weighed, it must be admitted that here is a solution of the prob- 
lem. 
The problem has been attacked from other points of view. 
Thus, Henry Fairfield Osborn, in an article in \Ai^ American Aat- 
uralist,'^ shows the plausability of the transmission of functional 
changes being the method of evolution in organic life. It is too 
much to assume, he says, that the tubercles in the teeth of mam- 
mals have been formed in an}' way other than by the the transmis- 
sion of mechanical mouldings. Eimer, the friend of Weismann, 
is the author of an elaborate volume in which he presents an 
array of facts in support of the transmission theory. He lays 
special stress on the matter of the pigmentation of the races of 
man. He finds that in the Nile valley there is a gradation, as one 
passes from Alexandria .southward, in the color of the native 
races from an intense black to lighter complexions through vari- 
ous intermediate shades. How, he asks, are we to account for such 
gradations by the preservation of favorable variations? Is it not 
more logical to assume that they have been the direct effect of 
environment from generation to generation ? Eimer’ s work is 
written in German and J. T. Cunningham of England has trans- 
lated it. This author him.self is a firm believer in the transmis- 
sion hypothesis and is a frequent contributor to the subject. To 
him is due partly the prominence that the question occupies at 
the present time. 
We have considered thus far proofs from the a priori point of 
view and also deductive proofs. There remains but one class of 
evidence — experimental. The classic experiments of Brown- 
Sequard on the guinea pig, in which he attempted to show that 
epilepsy, caused by the severance of the spinal cord in adults was 
transmitted to the offspring, are now considered invalid since 
germs of disease maybe transmitted in the germ-cells as syphillis 
is known to be. There have been thousands of cases reported of 
the so-called transmission of mutilations. Absolutely no depend- 
ence can be put on the large majority of these because of insuffi- 
cient data. Moreover, regeneration is so general that it is a priori 
improbable that amputations and the like are ev'er transmitted. 
The acme of attempts at experimental proof is found in the 
work of John Cossar Ewart, the Scotchman. The experiments 
in breeding zebras, horses, sheep, dogs, rabbits, etc., that he has 
carried out are of the highest type of scientific work. Environed 
* American Naturalist, 23 : 561. 
