Page:Popular Science Monthly Volume 21.djvu/438

426 the tenth century. The sign for the earth,, a globe surmounted by a cross, indicating its Christian origin, may be traced to about the sixth century. Of the recently discovered planets, the sign for Uranus,, is a modification of the initial H of Herschel; and that for Neptune, , is derived from the trident of the sea-god. The attempt to give similar symbols to the smaller planets was abandoned after they began to be too numerous to be distinguished in this manner.

Obesity and its Treatment.—According to the observations published by M. de Saint-Germain, in the "Union Médicale," the great danger to be feared from obesity lies in the direction of lesions of the heart. Considerable differences exist relative to the influences of sex on the liability to the affliction, but M. de Saint-Germain believes that women are the more liable to it, and that in proportion as they are addicted to alcoholism, prostitution, or inactivity. It may be developed at any age, even as early as two years; M. Hillairet recently exhibited at the Academy of Medicine a little girl six years old who was wonderfully fat. Among the causes of obesity are mentioned excess of food and of alcoholic drinks, too much sleep, and occasionally marriage. Widowhood, which makes men fat, appears to have the contrary effect on women. M. de Saint-Germain illustrates his method of treatment by citing the example of one of his best friends who was most probably himself. Having grown to the weight of two hundred and thirty pounds, he tried to train himself down by the regulation method of treatment, and in six weeks lost twenty-nine pounds and all his strength. He then stopped, recovered his weight and his health, and suffered no particular change for eight years. Then he took to horseback riding, gymnastics, and fencing, varying his exercises occasionally, but always keeping them up actively, in the early morning hours. To these he added a severe regimen; no breakfast after his fatiguing exercises, but a cigar to sooth the stomach. Later a breakfast of two boiled eggs, a cutlet with salad and fruit, coffee without sugar or spirit, no bread or wine, but water or tea without sugar to drink; for dinner, no soup, a plate of meat, a dish of green vegetables, fruit, no bread or wine; no dining in the city; absolute self restraint. The result was a fall of his weight to two hundred and twelve pounds, and increased vigor.

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Reciprocal Parasitism.—M. Maxime Cornu has taken notice of a prolongation of the vegetative activity of the chlorophyl-cells occurring under the influence of a parasite. M. Schwendener has affirmed that lichens are really fungoid parasites on algæ, which they envelop with their filaments and at the expense of which they live; and his view has been confirmed by the investigations of Rees, Bornet, and Stahl. The principal argument which has been opposed to this theory is based on the difficulty of explaining how the alga continues to live, grow, multiply, and even acquire new vigor, instead of perishing in the toils of the parasite. M. Van Tieghem supposes, to explain