Page:Popular Science Monthly Volume 21.djvu/294

284 the first starts from ortho-nitro-benzoic acid, which yields isatin after successive treatment with phosphorus pentachloride, silver cyanide, caustic potash, and nascent hydrogen. The other, also by Baeyer, starts from ortho-nitro-phenyl-acetic acid, which, having been obtained synthetically from toluol, is converted into the amidoacid, then by the loss of water into a body called oxindol, from which isatin, and therefore indigo, can be obtained.

Tobaccoism.—M. Thorens has published some observations on angina pectoris caused by tobaccoism. His attention was called to the subject by the case of a patient who had most of the symptoms of angina pectoris, but in whom no cause for the affection could be found except excessive smoking. The patient smoked cigarettes, and swallowed the smoke, thus making the whole quantity of smoke pass through the lungs. Evidently the opportunities given for the absorption of smoke and nicotine in this case were colossal in comparison with those which would exist in a person smoking ten times as much, but in an open place and without swallowing the smoke. Another circumstance aggravating the affection was, that the patient smoked his cigarettes directly, without the intervention of a holder, so that the smoke reached his mouth hot, without any chance having been given for the condensation of any of the volatile products. His mouth was, moreover, in constant contact with the tobacco-leaves, so that the liability of absorption by the buccal membrane was greatly increased. Similar affections arising from similar causes had been noticed by Beau and M. Gélineau, a naval surgeon, both of whom observed that the trouble was mitigated when the use of tobacco was moderated. The case suggests a number of precautions to be observed by persons who will smoke but desire to do themselves as little harm as possible, among which are never to swallow or inhale the smoke; to avoid smoking in an inclosed place, or at least to have the room as large and as well ventilated as possible; and to put as considerable a distance as is practicable between the light and the mouth, always using for this purpose long-stemmed pipes or cigar-holders. The driest tobacco and that which is weakest in nicotine, should be preferred. M. Thorens exonerates tobacco from the charge of producing cancer, although it is of course liable to irritate a wound already made, or a surface that has already been injured by heat.

The Horse in America.—It has been generally believed that the horse was introduced into America by the Spaniards. Professor Marsh, on the other hand, has found abundant remains of probable ancestors of the horse in our Western geological formations; so that, if there were no horses before the Spaniards came, there must have occurred a failure of the race. Mr. E. L. Berthoud, of Golden, Colorado, believes that he has evidence that the Spaniards found horses in South America when they first visited it. Among the maps which he has recently received from Paris, in a collection of the fifteenth and sixteenth centuries, is one which Sebastian Cabot drew for the Emperor Charles V, representing his explorations of the La Plata and Paraná Rivers, and containing symbols of the animals and plants that he found. Among these symbols was that of the horse represented near the plains of the Gran Chaco, where the immense herds of that animal range to-day. He claims that this affords a fair presumption of the native origin of the race, for neither the Spaniards nor the Portuguese had then been long enough in the country (in 1527) for their horses to have escaped from Peru to the head of the Paraguay and Paraná Rivers and to have increased in numbers sufficiently to attract attention.

The Protective Organs of Plants.—Dr. A. Tschirch has recently published some interesting observations on the relations of the anatomical structure of plants to climate and location. In the first place, the adjustment of the breathing-pores appears to be adaptable to a variety of external conditions in different plants of the same family. In plants that grow in a moist atmosphere, the pores are exposed with but slight protection; while the means of protection appear to increase gradually as the habitat becomes drier, and reach the highest point in desert plants. The closed cells