[62] Trajan’s wall, between the Danube and the Euxine, at Kostenjie.
[63] There were no medical men in Rome for the first five centuries of her great career; and some have fancied that this fact explains the astonishing number of armies which the republic found no difficulty in sending into the field.
[64] When unassisted by other deleterious influences, the poison, though all but universal over the locality, may not be destructive. After the draining the Lake of Haarlem, the principal physician of the district informed me that in 2000 cases of ague he had not lost a patient.
[65] The choleraic ferment traversed in ships, no doubt, the Atlantic, as typhus had often done before; but there are grounds for believing that vegetable and animal matters in a state of rottenness (fermentation), floating about in the air, are not unfrequently transported to great and almost incredible distances. Ehrenberg and Humboldt have particularly insisted on this fact, and have spoken of distances traversed by these fermentable elements, which I hesitate to quote from memory. Assuredly they were very great, extending to some hundred miles from the seat of their origin.
[66] England has often paid a high price for the first steps in science. Mr. Papillion, in 1806, received from Government 10,000l. for the introduction of dyeing Turkey red; and his success was owing to his knowledge of the water proper for the operation, which must be void of fermentable bodies.
[67] The ammonia always present in the atmosphere is probably derived chiefly from the union of nitrogen and hydrogen; but much of it also no doubt has its source in the fermentation of animal and vegetable remains.
[68] Baron von Lynden.
[69] I have known many persons sickly from the effects of intermitting fever or malaria from a residence in warm climates, and who have suffered and perished from an injudicious treatment. Ill-formed or incomplete agues are extremely common, even in the south of England, in London especially. They show themselves under a variety of forms, and with much severity, in the cases of those who, having once visited a true malarious climate, are ever afterwards more or less liable to a return of the disease. Let men reflect; simple truths travel slowly, yet are truths notwithstanding. The death of the well-known M. Soyer was evidently caused by his wholly misunderstanding the nature of his complaint, which, in fact, was a fever originally caught in the Crimea.
[70] A friend who resided long on the Grotevisch Rivière, and in het land den Caffre, informs me that if the Zuureveld be ploughed up, or altered by the burning, for example, of a Caffre hut, the sour grass, whence the district derives its name, disappears, and sweet herbage of various kinds take its place. None of these exist naturally in the district, so that the seeds must come from great distances.
[71] The effects of partial and incomplete drainage have ever been the same. In 1823, when the new Polder was made at Neusen-on-the Sheldt, small-pox raged in the neighbouring villages to such an extent that the children were forbidden to attend school. The effects are to be seen now in persons over sixty years of age, bearing the marks of the epidemic. The whole atmosphere of the district was infected.