Page:Popular Science Monthly Volume 5.djvu/523

Rh Here, therefore, the weeds and ferns hold and preserve the mounds, not only as the better soil, but also as the drier spots.

The Value of Vivisections.—Prof. M. Schiff, of Florence, whose vivisections gave rise to the recent controversy on the cruelty of the practice, has published a book, in which he states the results of his experiments. The following quotations from this work will best show whether, as the opponents of vivisection have claimed, experiments of this kind "lead to no useful result," or are to be classed as "acts of needless cruelty." Prof. Schiff has studied the comparative effects of ether and chloroform on the animal economy. Ether, according to him, is preferable to chloroform as an anæsthetic, because etherization, even when pushed to the very last stage of insensibility, is never dangerous to life, so long as one maintains the act of respiration. And even if one presses the inhalation of ether still further, so that the respiratory movements cease, life is never menaced, if, at the moment of the paralysis of the thoracic walls, artificial respiration is immediately commenced. Chloroform has been preferred to ether because it acts more quickly, and its use is more agreeable to some persons. But chloroform has a paralyzing action much greater than that of ether, and, in like manner, has a special influence on the nerves of the heart, and of the vessels. If the inhalation of chloroform is carried so far as to produce a considerable weakening of the respiratory movements, the interruption of the inhalation may, in a majority of cases, lead to the reëstablishment of respiration, and, afterward, of sensation; but sometimes, in a few moments after the commencement of inhalation, the force of the circulation is so enfeebled that the blood passes sluggishly through the lungs, and its rate of renewal or revivification is much diminished. The blood in the body no longer comes into necessary contact with the atmospheric air introduced by respiration into the lungs. If the action of chloroform is prolonged until respiration ceases, we are not even sure of being able to revive the person, after having reëstablished the respiratory movements; for these often again cease, owing to the disturbance of the circulation, while these same movements, if restored after the inhalation of ether, become always more frequent in the patient when left to himself. Prof. Schiff affirms that, in the present state of science, the medical man is responsible for every case of death occasioned by the application of ether, because a careful watching of the respiration is capable of preventing death, while the fatal effect of chloroform depends, in part, on individual predisposition, which the physician is unable to recognize.

Animals and Fire-arms.—That crows and many other species of birds have little fear of man when he is unarmed is a familiar fact, and suggests that they fear him chiefly because of the weapons he carries. In Scotland, where shooting was prohibited on Sunday, crows and rooks were gentle, and fed around buildings without concern. Singularly enough, the same thing was observed of animals by Dr. Tristram when traveling in the wilderness of Moab, where the sound of a gun is quite rare. He says: "We were struck with the sagacity which all the wild animals showed in the matter of fire-arms, little familiar as they can be with them here. As it was Sunday, we strolled or sat down among the ruins without our fowling-pieces, and were consequently objects of indifference. A fine fox sat and looked at us a dozen times among the stone-heaps, and just walked away, keeping almost within gunshot all the afternoon. The Sakkr falcon sat calmly on his favorite perch, and allowed us to reconnoitre him on Sunday, while the eagle, owls, sand-grouse, and partridge, showed a similar contempt for unarmed Europeans."

The Temperature of the Ocean.—Dr. Carpenter recently delivered a lecture before the London Royal Institution, on the "Temperature of the Ocean," showing, from the soundings made by the Challenger Expedition, that the difference of climate between Northwestern Europe and the North American Atlantic seaboard is due not to the course of the Gulf Stream, but to the circulation of the waters of the Ocean between the poles and the equator. The shores of Northwestern Europe have the benefit of the northward movement of the warm