Page:Popular Science Monthly Volume 20.djvu/438

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424
THE POPULAR SCIENCE MONTHLY.

the water with its mouth wide open, a constant stream passing in at the front, through the upright whalebone plates at the sides, and out again at the back. The small animals which form its food are entangled in the long hairs which fringe the internal edges of the plates, and from time to time, as they become collected in sufficient numbers, the whale closes its mouth, raises its tongue, and swallows the mass." Its favorite food is a black pteropodous mollusk, resembling a humble-bee, and, after this, jellyfish, of which it takes millions to make a meal. Fortunately for the whale, these creatures go closely massed together in shoals many square miles in extent. After man, the whale's worst enemy is the grampus, which attacks it savagely, and is very destructive to the species. Its protection from both enemies is the ice; and it is, consequently, now found almost exclusively in the neighborhood of ice.

 

Typography and Eyesight.—Dr. Javal considers the subject of typography in relation to the hygiene of the eyes in the "Revue Scientifique." His conclusions differ materially only in a few points from those which Professor Herman Cohn has published. He believes it important to make the several letters, particularly those which are allied in form, as distinct as possible, and therefore favors those fashions in the cutting of the types which tend to accentuate the distinctions. The superior importance of the upper part of the letters, which is generally recognized, is enforced by the fact that in the case of the irregularities in the lines occasioned by the "long letters," eighty-five instances occur in which the long strokes rise above the line to fifteen in which they fall below it. Of the groups of letters resembling each other the members of the one composed of a, c, e, o, and s, are most likely to be confounded with each other, and more clear distinctions in the formation of their upper curves are eminently desirable. The strokes of which the letters are composed should not be made so thick as to blur the figure of the whole letter, which is the feature the practiced reader regards; and only young readers require a particularly heavy stroke. The thin lines that cut off the strokes at either end are not without importance; and Dr. Javal prefers the English method of drawing them so as to leave a curve between the stroke and the line, to the French method of leaving a sharp angle. These lines may be used with good effect, with slight variations in their position to assist in marking distinctions between letters which are otherwise somewhat alike. Dr. Javal regards the width of the letters as of more importance than their height, and the spacing between them as of more moment than the separation of the lines by leads; he does not consider leaded matter as really more legible than "solid"; and he ascribes a superior legibility in English books to the predominance of short words, giving more horizontal spacing. He would prefer a large type "solid" to a finer type leaded, although he admits that a "solid" page has a blackish, heavy, and somewhat disagreeable aspect. If attention is paid to his views regarding the breadth of the letters and the inter-literal spacing, he believes that the height, in the case of ordinary reading matter, may be considerably reduced without marring the legibility. Different considerations must prevail in regard to schoolbooks, in which the typography must vary according to the age of the pupil, within limits which can be determined only by experience.

 

Accommodative Cultivation of Infections Organisms.—Dr. A. Wernich has considered, in "Kosmos," the extent to which the molds, the microbic parasites of the body, and the germs of infection, are able to adapt themselves to new conditions of existence, assume new forms, and produce different effects. When microbes are observed in great numbers, as they may be sometimes in the tissues and secretions even of healthy persons, much more of sickly ones, the temptation is very strong to associate them with the production of disease, and is apt to mislead. Naegele has expressed himself in favor of the doctrine of transformation, and says that the same fungoid, transferred successively from one medium to another, may produce, in milk, lactic acid; in meat, putrefaction; in wine, gum; in the ground, nothing; in the human body, disease; and that it may, in each