and disastrous experience of it are much more resistant than those that have had little or no experience of it. Even people who strenuously repudiate the idea of evolution in general, must admit that in this case evolution has certainly occurred; for if, as they usually believe, all the races of mankind had a common origin, and were therefore originally alike, then in no other way is explainable the difference that now exists between one race and another; not only as regards disease, but also as regards size, colour, shape, &c.—e.g. between the Englishman and the West African negro. The only question possible is as to how this evolution occurred—as to what are the factors of it. Has it been by the accumulation of inborn traits, or by the accumulation of acquired traits, or by the accumulation of both? This question has already been dealt with; there can be no doubt that it has resulted solely from the accumulation of inborn traits.
But while this evolution, when once attention is drawn to it, becomes so manifest, that we need not waste time in marshalling in proof of it facts that are notorious, we shall nevertheless find it interesting to note how exactly the degree of evolution undergone by any race coincides with the virulence of the disease to which it has been subjected. This fact is admirably brought out in the following—
"In Ceylon there died of malarial fevers per 1000 of the population—
| Negroes | 1·1 | |
| Natives of India | 4·5 | |
| Malays | 6·7 | |
| Natives of Ceylon | 7·0 | |
| Europeans (English) | 24·6 | [1] |
- ↑ Hirsch, Geographical and Historical Pathology, vol. i. p. 245,
