Page:Popular Science Monthly Volume 41.djvu/290

278 the counties into three groups—those in which there were, respectively, $8⁄100$ of an acre, 1·4 acres, and 4·8 acres to each person, the corresponding rates of mortality from diphtheria and croup were 12·7, 10·2, and 8·8 annually for every 10,000 persons. The relation of certain railway lines to the diphtheria death-rate is worthy of note. It was comparatively high in the greater number of cities and towns traversed by the Boston and Albany Railroad—a leading road for traffic, carrying large numbers of passengers, and having many stations; was less upon the line of the Fitchburg road, which is of about the same length but does less business; and still less upon the line of the more recently built Massachusetts Central road. The term diphtheria first appeared in the registration reports of the State in 1858. The number of deaths assigned to it increased rapidly till 1863, when 1,420 were registered. There was then a rapid decline to 251 in 1867, after which the annual number continued nearly uniform (about 275) for seven years, when it rose again to 2,610 in 1876 and 2,734 in 1877. The census of 1890 gave the number of deaths as 32,716. The diphtheria death-rate bore no relation to the general death-rate, except during the period from 1862 to 1867. In 1872, when the general mortality-rate was at its highest point and infectious diseases were generally very prevalent, the diphtheria death-rate was far below the mean, and in 1876 and 1877, when the general death-rate was near the mean, the diphtheria death-rate was at its highest point. The author concludes, further, that diphtheria is eminently contagious; that it is infectious by direct exposure and through indirect media, but less so than some other diseases, such as small-pox and scarlet fever; that overcrowding, faulty ventilation, and filthy conditions favor its spread; that the direct influence of plumbing and transmission through public and private water-supplies is not proved; that its propagation is favored by soil moisture, damp cellars, and general dampness of houses; and that the poison may remain dormant in houses for a long period.

Scientific Observation of Children.—In a paper on this subject addressed primarily to mothers, Mrs. Helen Adler has laid out a plan of work of considerable scope, and calling for the exercise of careful judgment. Mothers, the author says, "must first of all learn to appreciate the value of true scientific observation, must train themselves to observe correctly, methodically. They must humbly learn that their own powers of appreciation are worthless without the strict selection of valuable facts, the subordination of what is interesting and delightful to them to the universally interesting and profitable. . . . Method, strict, logical method, is the first desideratum; then vigilant observation, veracity, discrimination, and ingenuity in the study of the child. Baby ways are charming and irresistible; they will be no less so when an attempt is made to discover the order of progress that dwells in them." The development of language alone is mentioned as offering a fascinating field of observation; the study of the baby will and its evolution another; and the psychic life of the child will seem somewhat nearer to us, the growth of its faculties a little more clearly revealed, if we trace the record of their development day by day. Later in life comes the development of the character of the child as a social being. A practical direction is given to these observations by appending to them a classified schedule of the points to which attention may be directed.

Olives and Olive Oil.—The olive is cultivated on about seventy thousand acres in the department of the Alps Maritimes, France, and yields a revenue of more than two million dollars a year. Two species of the tree are described by our consul at Nice as growing in the south of France: the oleaster, or wild olive, which has a kind of thorn and very short leaves, and produces only a few small berries, which appear to be proof against insect enemies; and the sativa, or cultivated olive, which produces a large fruit, and is known in several varieties. The olive tree flowers every year; but, while some growers advocate an attempt to gain a yearly crop, the majority are content to try to get a good crop every two years. Olives to be preserved green are plucked in September; those destined for oil, from November till the following May; but the best results to crop and tree seem to follow harvesting near mid-winter when the olive is black; while oil made from olives gathered as late as February and