It was not Mr. Darwin’s manner to put his reader on his guard; we might as well expect Mr. Gladstone to put us on our guard about the Irish land bills. Caveat _lector_ seems to have been his motto. Mr. Spencer, in the articles already referred to, is at pains to show that Mr. Darwin’s opinions in later life underwent a change in the direction of laying greater stress on functionally produced modifications, and points out that in the sixth edition of the “Origin of Species” Mr. Darwin says, “I think there can be no doubt that use in our domestic animals has strengthened and enlarged certain parts, and disuse diminished them;” whereas in his first edition he said, “I think there can be _little_ doubt” of this. Mr. Spencer also quotes a passage from “The Descent of Man,” in which Mr. Darwin said that _even in the first edition_ of the “Origin of Species” he had attributed great effect to function, as though in the later ones he had attributed still more; but if there was any considerable change of position, it should not have been left to be toilsomely collected by collation of editions, and comparison of passages far removed from one another in other books. If his mind had undergone the modification supposed by Mr. Spencer, Mr. Darwin should have said so in a prominent passage of some later edition of the “Origin of Species.” He should have said—“In my earlier editions I underrated, as now seems probable, the effects of use and disuse as purveyors of the slight successive modifications whose accumulation in the ordinary course of things results in specific difference, and I laid too much stress on the accumulation of merely accidental variations;” having said this, he should have summarised the reasons that had made him change his mind, and given a list of the most important cases in which he has seen fit to alter what he had originally written. If Mr. Darwin had dealt thus with us we should have readily condoned all the mistakes he would have been at all likely to have made, for we should have known him as one who was trying to help us, tidy us up, keep us straight, and enable us to use our judgments to the best advantage. The public will forgive many errors alike of taste and judgment, where it feels that a writer persistently desires this.