Page:Popular Science Monthly Volume 7.djvu/395

Rh Statistics of Suicide in Prussia.—The number of suicides occurring in the kingdom of Prussia during the four years preceding 1873 is given as follows in the official journal of the Statistical Bureau:

From this it would appear that either the female sex is less exposed to the temptation of suicide, or resists that temptation better than the male. The table shows that the frequency of suicide increases with age. This is true with regard to the whole number of suicides, not with regard to those of each sex taken separately. Thus suicide is most frequent among males between the ages of ten and fifteen, and again between fifty and sixty, while among females it is most frequent between fifteen and twenty, and again after seventy. Of suicides, married persons constitute 452 per 1,000, unmarried, 339 per 1,000, and the remainder is made up of widows, widowers, divorced persons, etc. Mental disease is by far the most frequent occasion of suicide. Religious belief does not appear to have any marked influence. On the other hand, the influence of various avocations is very evident. The favorite modes of suicide are, in both sexes, hanging and drowning—the latter more frequent in the case of females; then by fire-arms on the part of the males, by poison on the part of the females.

Defects of the Human Eye.—The human eye, because it is practically achromatic, has been supposed to be absolutely so. But it is not difficult to show that the organ is not faultless in this respect. The subject was recently discussed in a lecture by Prof. H. McLeod, at the London Physical Society, and the lecturer cited many facts to show that the eye is not achromatic. Thus to short-sighted persons the moon appears to have a blue fringe. In using the spectroscope, the red and blue ends of the spectrum cannot be seen with equal distinctness without adjusting the focusing glass. A black patch of paper on a blue ground appears to have a fringed edge if viewed from even a short distance; while a black patch on a red ground, when observed under similar conditions, has a perfectly distinct margin. It is interesting to note that Wollaston considered that the colored bands of the spectrum were really divided by the black (Fraunhofer) lines, and his statement, that the red end of the spectrum does not appear to have a boundary-line "because the eye is not competent to converge the red rays properly," shows that he had very nearly, if not quite, discovered the achromatic defects of the eye. An experiment was exhibited by Prof. McLeod to show the relative distinctness of a dark line on grounds of various colors. A wire was so arranged that its shadow traversed the entire length of the spectrum, which was thrown on a screen by an electric lamp. Viewed from a short distance, the edges of the shadow appeared to be sharp at the red end, but gradually became less distinct, until at the blue end nothing but a blurred line remained.

Infrequency of Pulse.—A case of extraordinary infrequency of pulse was recently mentioned by Mr. Pugin Thornton, at a meeting of the Clinical Society of London. The subject was a woman, twenty-nine years of age, thin and anæmic, and suffering from severe inflammation of the larynx, for which the operation of tracheotomy was performed. Just before the operation her pulse was 40, and after it she had an epileptiform attack. She was discharged from the hospital much improved, but was readmitted soon afterward. Her pulse was then found to be beating only at the rate of 16 per minute, the pulsations being strong. The frequency increased slowly for a month, when it was 20, and soon afterward it was again 40. This was some two years ago. Her pulse is now 48, and the patient has grown stout. Normally, the number of pulsations per minute differs at different periods of life: at birth, it is about 135; at the age of seven, from 80 to 85; in adults, 70 to 75; in old age, from 50 to 65. In females, the pulse is quicker than in males.

Ornamentation of Copper and Bronze.—A new mode of ornamenting bronze or copper work is described as follows: After the object has received the desired form, the