Our ignorance of the laws of variation is profound.

我们对变异规律的无知是深刻的。

In the next chapter I shall discuss the complex and little known laws of variation.

在下一章中， 我将讨论复杂且鲜为人知的变异定律。

In many other cases, modifications are probably the direct result of the laws of variation or of growth, independently of any good having been thus gained.

在许多其他情况下， 变化可能是变异或生长规律的直接结果， 与由此获得的任何好处无关。

A grand and almost untrodden field of inquiry will be opened, on the causes and laws of variation, on correlation, on the effects of use and disuse, on the direct action of external conditions, and so forth.

一个宏伟而几乎无人涉足的研究领域将被打开，涉及变异的原因和规律、相关性、使用和废弃的影响、外部条件的直接作用等等。