NATURAL HISTORY. CENTURY VIII. Experiment solitary touching veins of medicinal earth. 701. THERE be minerals and fossils in great variety; but of veins of earth medicinal, but few; the chief are, Terra Lemnia,1 Terra Sigillata communis, and Bolus Arminus; whereof Terra Lemnia is the chief. The virtues of them are, for curing of wounds, stanching of blood, stopping of fluxes and rheums, and arresting the spreading of poison, infection, and putrefaction: and they have of all other simples the perfectest and purest quality of drying, with little or no mixture of any other quality. Yet it is true that the Bole-Arminic is the most cold of them, and that Terra Lemnia is the most hot; for which cause the island Lemnos, where it is digged, was in the old fabulous ages consecrated to Vulcan. Experiment solitary touching the growth of spunges. 702. About the bottom of the Straits2 are gathered great quantities of spunges, which are gathered from 1 See, for some account of Terra Lemnia, Sandys's Travels, p. 18. (7th edition). 2 That is, the Hellespont. See Sandys, p. 14. moss. the sides of rocks, being as it were a large but tough It is the more to be noted, because that there be but few substances, plant-like, that grow deep within the sea; for they are gathered sometimes fifteen fathom deep and when they are laid on shore, they seem to be of great bulk; but crushed together, will be transported in a very small room. Experiment solitary touching sea-fish put in fresh waters. 703. It seemeth that fish that are used to the salt water, do nevertheless delight more in fresh. We see that salmons and smelts love to get into rivers, though it be against the stream. At the haven of Constantinople you shall have great quantities of fish that come from the Euxine Sea; that when they come into the fresh water, do inebriate and turn up their bellies, so as you may take them with your hand.1 I doubt there hath not been sufficient experiment made of putting sea-fish into fresh-water ponds and pools. It is a thing of great use and pleasure; for so you may have them new at some good distance from the sea: and besides, 1 Sandys, p. 23. Modern experience has confirmed what Sandys here relates; but there is no reason to suppose that the fish have any enjoyment in the state of half insensibility which the change to fresh water produces. The cause is probably to be sought in what appears à priori to be certain, namely, the rapid absorption through the gills of fresh water. All the conditions appear to be present by which absorption by endosmosis is occasioned. The periodical migrations from salt to fresh water, and vice versa, of certain kinds of fish may perhaps be connected with a change in the composition of the blood, determining endosmosis or exosmosis through the gills, and consequently rendering the fish uneasy in its actual position. Has it ever been suggested that the persevering way in which salmon ascend rapid streams may result from the unequal velocity of the water at different depths? The consequence of this variation would be a sensation of greater pressure against the lower part of the body than on the upper; which under certain circumstances may be agreeable. |