Intellectual Acquirements.—Not to depend on such evidence, however, he adduces that of a very different character, namely, the non-transmission of intellectual acquirements. Language is an example. Although human beings have been communicating their thoughts to each other from very ancient times by speech, yet every child has to learn how to do this for itself. No matter how many languages the parents master, their children have to go over all the ground the parents did, make all the toil and effort to learn to speak. The children of the most gifted linguists, if brought up without coming in contact with those who can teach them to talk, will never learn a single word. There are, it is claimed, a few cases on record of children who never acquired their natural tongue because they had lived among animals and not among human beings. They learned to make the same vocal sounds the animals did, no more. The environment in this case was everything, the parental acquirements nothing.
Music, like language, is also an acquired character, and it is probably not transmitted. Our musical geniuses are not the children of great musicians, but in most cases the reverse. They seem to spring into existence from lowly sources, or at least from parents whose advantages for a musical education have been very limited, though generally they have had good health, and a climatic environment of a favorable kind. Great musical talent usually dies out in any family in a few generations, no matter how much it is cultivated, or, if it does not die out entirely, it becomes mediocre; and yet the opportunities of the children of great musicians, and the ambition of their parents for its culture, are usually very favorable.
Instinct.—In accepting the theory of the non-transmission of acquired characters, it becomes necessary to give up prevailing views of the origin of instinct. According to the old belief it was a gift of God, and not acquired by any effort on the part of its possessor. In speaking of the instinct of bees, Sidney Smith says: "Providence has done it. There are the bees, there is the comb, and the honey, get rid of it or find some other explanation if you can."
The early evolutionists changed all this, and made instinct the inheritance of an oft-repeated act. The young kitten, as soon as old enough, hunts for a mouse and catches it without any training. The sight of the mouse acts on its nervous system in such a way as to compel it to creep up softly, jump on it, toy and play with it, and finally kill and eat it. It would have required long practice on the part of its ancestors before so wonderful a character could have become fixed. The same is true of the setter dog.
The new view is, that instincts arise from variations in the germ-plasm. The union of the germ elements of two individuals causes it to vary more or less from either parent. These variations will be favorable and unfavorable. The unfavorable ones will produce offspring handicapped in the struggle for life and they will disappear. The favorable variations will produce descendants possessing advantages for survival and leave numerous offspring.
It is not easy to accept this view, but I think there are some facts that support it. I will advance a few. The hive of the honey-bee contains three kinds of insects: the queen, the drones or males, and the workers. The queen makes her nuptial flight but once in a life-time, and does it from instinct. How can an instinct like this have been acquired by being performed but once? The drones are derived from unfertilized eggs; yet their instincts are those of the male, not of the female. As they have no male ancestors, it seems probable there was in the germ-plasm of some queen bee, at a time far back, some change which allowed unfertilized eggs to produce males.
The workers are all females, not fully developed sexually on account of a diet with too small a proportion of nitrogenous food and containing so large a proportion of the hydrocarbons. They inherit from the mother, or rather from the germ-plasm, the instinct to gather honey, yet neither their male nor female ancestors ever gathered any honey in their lives, nor have they for ages. Far back in antiquity the queen, no doubt, did gather honey, but the disuse of this instinct has not caused it to disappear in the working bee, as it should have done according to the Lamarckian theory of disuse causing decay of function. Is there any way to account for this, except on the theory that the germ-plasm produces working bees as well as the other kinds, irrespective of the habits of the queen? Her character in this respect is fixed and does not change. Is it unreasonable to think that some time in the past, in some queen bee, was formed a germ-plasm capable of producing three varieties, and that there was such an advantage in it for survival, that it has been continued ever since by natural selection? Queens not able to do this have not been selected, left no offspring, and thus the perfection of the stock has been assured.
One more case. Some years ago, when interested in agricultural entomology, I made a study of the so-called seventeen-year locust. Noting the wonderful precision with which the female cuts into a soft twig of a tree and lays its eggs in two rows, the thought was suggested to me, how can an instinct, used only a few hours, once in seventeen years, be acquired by exercise and persist in the offspring seventeen years later? Weismann's theory of the origin of instinct from favorable variations in the germ-plasm offers, it seems to me, a rational explanation.
I do not need to extend illustrations which abound in the insect world, especially among the ants, which furnish cases of coadaptation that cannot be transmitted, as they do not propagate, so I will not mention them here.
Now, if acquired characters are not transmitted to offspring, how should these facts affect our methods of educating children?
