observed was three times less among the former than among the latter."—Hirsch, Geographical and Historical Pathology, vol. i. pp. 244–5.
In other words, the Europeans, to whose race the disease was strange, suffered three times as much from the disease in its severer forms as the natives, to whose race it was familiar—a fact to which many parallels may be found. Thus Professor Hirsch remarks—
"In the malarious regions of the tropics the natives take the milder forms of the fever, while the foreigners, and particularly those not acclimatized, take the disease in its severer forms; and, in accordance with that fact, the types with the longer intervals occur in the former, and those with the shorter intervals in the latter."—Ibid. vol. i. p. 241.
"Just as the history of malarial disease shows it to have been a malady of all times, so the inquiry into its geography leads us to recognize in it a disease of all races and nationalities. This predisposition to malarious sickness is developed to the highest degree among all the peoples belonging to the Caucasian stock, not only on European soil, but also among the Arab population of the Barbary States, and in the malarious districts of India, where the Mahommedan and Hindu population suffer in the same degree as foreigners. This is not the less true for the Malay and Mongol stocks, and for the native (Indian) population of North and South America. The predisposition is least for the Ethiopian race, which, although it by no means enjoys an absolute immunity from the disease, is still affected by it, ceteris paribus, less frequently, less readily, and less severely than other races; and to this many experiences have incontestably testified, not only in Senegambia, the West Coast of Africa, Nubia, and other parts of its native habitat, but also in other malarious regions of the tropics whither they have migrated. This relative