Page:Popular Science Monthly Volume 9.djvu/404

 by distillation from oil of thyme, occurs in white, highly-aromatic crystals; when dissolved in hot water in the proportion of one part per 1,000 it forms a fully-saturated solution possessing a neutral reaction. More concentrated watery solutions cannot be obtained, for, when dissolved in greater proportions than one in 1,000, the thymol evaporates. Lewin finds that 0.1 per cent, of this solution is sufficient to prevent fermentation in sugary liquids, no matter what the proportion of sugar and yeast. Milk to which a small quantity of the thymol solution was added did not begin to show signs of coagulation till twenty days later than milk with which an equal quantity of water had been mixed. Filtered white of egg in contact with the air was found to grow putrid in three or four days, whereas white of egg with which thymol-water had been mixed gave not the slightest indication of putridity after eleven weeks. The same results were obtained in treating pus with water and thymol: pus so treated at once lost its putrid odor, and continued to be odorless for five weeks, or until it had become dry.

The English Commission on Vivisection.—The Royal Commission appointed in England to inquire into the subject of experimentation on living animals, for scientific purposes, have reported unanimously against the absolute prohibition of this practice. "Our conclusion is," says the report, "that it is impossible altogether to prevent the practice of making experiments upon living animals for the attainment of knowledge applicable to the mitigation of human suffering or the prolongation of human life; that the attempt to do so could only be followed by the evasion of the law, or the flight of medical and physiological students from the United Kingdom to foreign schools and laboratories, and would, therefore, certainly result in no change favorable to the animals; that absolute prevention, even if it were possible, would not be reasonable; that the greatest mitigations of human suffering have been in part derived from such experiments; that by the use of anæsthetics in humane and skillful hands the pain which would otherwise be inflicted may, in the great majority of cases, be altogether prevented, and in the remaining cases greatly mitigated; that the infliction of severe and protracted agony is in any case to be avoided; that the abuse of the practice by inhuman or unskillful persons—in short, the infliction upon animals of any unnecessary pain—is justly abhorrent to the moral sense of Englishmen generally, not least so of the most distinguished physiologists and the most eminent surgeons and physicians; and that the support of these eminent persons, as well as of the general public, may be confidently expected for any reasonable measures intended to prevent abuse."

Perception of Musical Tones.—From the researches of Prof. Preyer, of Jena, on the "Limits of Perception of Musical Tones," it appears that the minimum limit for the normal ear is from sixteen to twenty-four vibrations per minute, and the maximum forty-one thousand vibrations, though persons with average powers of hearing were found to be absolutely deaf to tones of sixteen thousand, twelve thousand, or even fewer vibrations. Silence, according to Preyer, is a state of uniform minimum excitation of the auditory nerve-fibres. Silence is to the ear precisely what black is to the eye. The pressure of the fluid contents of the labyrinth and the flow of blood through the vessels must give rise to sensations of which we are unconscious only because of their uniformity, their constancy, and their low degree of intensity. Silence, when the attention is concentrated on the sense of hearing, is found to vary in degree just as the blackness of the visual field, when light is excluded from the eye, has been observed to vary. Lastly, the parallel between the auditory sense and the visual is borne out by a study of the entotic (intra-aural) sensations, which are closely analogous to well-known entoptical (or intra-ocular) phenomena.

Dr. Mohr on the Source and Composition of Meteorites.—From an examination of a large number of meteorites, Dr. Mohr, in Liebig's Annalen der Chemie, concludes that these bodies must have been formed upon a planet warmed by the sun, or by a sun in absolute rest, and in the lapse of an enormous length of time. Under what circumstances this planet has been shivered