Art. X.—On Hereditary Knowledge.
[Read before the Wellington Philosophical Society, 11th July, 1899.]
I remember reading about the young swallows taking their flight from England when they had been only a few days on the wing; and, when we know nothing to the contrary, we are likely to assume that their parents led them away and taught them the geography of the country they were going to. But I have seen young “shining cuckoos” at Te Anau as late as April, apparently alone and quite happy, though they had a thousand-mile flight before them immediately, if they wished to survive; and no one to show them the way, for it is probable that a young cuckoo never sees its mother except by accident.
As far as our knowledge goes, the cuckoos leave their eggs and young entirely to foster-parents, who are not likely to teach
any cuckoo lore. Therefore the knowledge of geography and their own peculiar impressions must have been laid in the egg, or, in other words, must have been hereditary; and why not the same with the swallows ?
If the parent swallow has to lead her young and point out routes and localities, it is a very poor plan compared with that of the cuckoos; because, if anything happened to the parents, or if they were getting old or weakly, their young would perish with them for want of the knowledge that could as well have been laid in the egg.
Every one knows that a trout will teach nothing to its young ones, but will eat them at the first opportunity; yet they know all about visible fishing-lines, and the way to ascend rivers and rapids at the appointed time, which must be hereditary, when they had no experience and no teachers.
The young snipes, flying away to some far-off country, may have all the geographical knowledge that/their parents had gathered for ages as to where and when to find the marshes and springs that shelter their food in a land that they had never seen, and probably never heard of. Therefore the long flights of migratory birds may be directed by knowledge derived from far-distant parents that first made their journeys when land was almost continuous.
What a wonderful thing is mind, of which we seem only to have a part, deficient in valuable faculties that other animals possess—deficient in memory and thought, and in the power of transmitting or even retaining the hard-earned acquirements that our youngsters need so much.
However, I saw recently in Dunedin what I take to be a case of hereditary aptitude in a little boy, who was better read and more intelligent at nine years of age than many boys at sixteen. And when we remember our progress in the last generation there appear great possibilities in the next few thousand years, which will skip away like hours when our time is up. Then, if any of us are allowed to look back at this old world, we may see hereditary knowledge becoming a part of men's minds, and ignorance and imposture things of the past. The power of heredity to improve we readily admit among animals, but ignore in ourselves, not because its laws are so obscure, but because our whims are easier to follow; and, though we experiment in all other branches of science, this, the most important of all, we have hardly the courage to touch.