We shall have to recur to this subject; and I will here only add that their variability seems to result from their uselessness, and consequently from natural selection having had no power to check deviations in their structure.

我们将不得不重新讨论这个问题； 我在这里只补充说， 它们的可变性似乎是由于它们的无用性造成的，因此自然选择没有能力检查它们结构中的偏差。