We can by cultivation of our minds and morals not only increase our own powers, but add to the powers of our posterity.
Then, too, the effects of mental education are transmissible; not the education itself, but an increased capacity, a new tendency. Every mental activity is accompanied by an actual modifying influence on brain structure, so that we are really building our brains by our thoughts, and this increase of our own brains is transmissible to posterity.
I know that some of our philosophers assert strongly that acquired characteristics are not transmitted, and their theories seem quite plausible; but I would rather accept facts than theories any time, and Professor Elmer Gates has demonstrated that this theory does not accord with the facts. He has trained dogs until they could recognize seven or eight shades of green or red. The brains of these dogs, so trained, show under the microscope a great increase of brain-cells in the visual area, proving that the education has created actual brain material. The progeny of these dogs, to several generations, shows at birth a much larger number of brain-cells in the visual area than is the case where the ancestry has not been so strained.
Where the dogs have been brought up in absolute darkness there is a great lack of cells in the visual area, both in these dogs and in their progeny.
This is the brief statement of a most hopeful and encouraging fact.
We look to the dark side of the law of heredity for our warning. It makes us solemnly thoughtful in view of our power over the race in the transmitted result from our own wrongdoing; and then, when we feel overwhelmed and discouraged, we turn towards the Gospel of Heredity and take hope from the fact that good is transmissible; and, more than that, we have it in our power so to modify our own characters, tendencies and habits that we can, in all probability, give our children a better dower than we received, and the earlier in life we begin this making over of ourselves the better.
I have heard people excuse themselves for all manner of faults on the plea that they were inheritances, and therefore could not be overcome. That is to declare that we are slaves, with no chance to acquire freedom, and I am not willing to admit that.
"Whereas in Adam all die, in Christ may all be made alive." That is, that while under the Law of Heredity we are fettered, under the Gospel of Heredity our chains may be broken and we become free.
There is much of encouragement in the poem of Ella Wheeler Wilcox on heredity:
"There is no trait you cannot overcome.
Say not thy evil instinct is inherited,
Or that some trait inborn makes thy whole life forlorn,
And calls for punishment that is not merited.