[64] Darwin's Botanic Garden. P. 256.
[65] To prove that salt is absorbed into land plants growing near the sea, the following facts, for which I am indebted to my friend, Dr. D. V. Knevels, are conclusive. The fruit of those cocoa-nut trees which grow near the seashore in the West-Indies is generally found to have a saltish taste; and even the milk in the nut is perceptibly impregnated with it. Those trees on the contrary which grow in the interior, beyond the influence of salt water, have their fruit perfectly fresh and sweet.
The same gentleman informs me, that in a plantation of his father's, in the West-Indies, situated on the seashore, a whole crop of the cane was rendered unfit for the purpose of making sugar, in consequence of the great quantity of salt which it had imbibed.
[66] Journal of Science and the Arts. No. X.
[67] Volney's Travels in Syria and Egypt, Vol. I. p. 167.
[68] On the subject of the Egyptian ophthalmia, it may be asked "why it does not appear in innumerable other situations, equally exposed to salt air, as Cape Cod, and the West-India Islands?" To this it may be replied, that in the production of any disease whatever, a predisposing state of the system is as necessary as an exciting cause. This predisposition appears to exist in a great degree among the Egyptians, and depends upon the nature of their climate, their habits, and mode of living, all of which have a tendency to produce debility of the eyes, and thus render them more susceptible of the impression of those causes which excite inflammation.
[69] Rush's Medical Observations and Inquiries, Vol. II. p. 132.
[70] Volney's Travels, Vol I. p. 226.
[71] Rush's Observations and Inquiries, Vol. II. p. 133.
[72] This was most remarkably perceived on one occasion, where, under the idea that possibly chrome might exist in the ores, they had been intensely heated in a forge along with pearl ashes. The mass, when lixiviated, gave only a greenish solution, becoming colourless by nitric acid, and again greenish by an alkali; this was supposed to be owing to iron and manganese. No metal was obtained, except a few minute globules of attractable iron, but the laboratory was filled with white fumes, having the peculiar odour alluded to.