Page:Popular Science Monthly Volume 84.djvu/267

Rh schools with forenoon sessions only. This is shown in the following table.

Both Hertel and Schmid-Monnard found that the percentage of morbidity rises considerably toward the end of the school year. Mortality, also, slightly increases for a brief period after school entrance, as does also the incidence of infectious diseases.

The most extensive and important single investigation of this kind yet made is that carried out by the Russian Department of Education, the results of which were reported by Khlopine in 1911 (10). This investigation was essentially a sanitary census of all the secondary schools of the Russian empire, carefully and uniformly carried out under the direction of the chief medical officer of schools, and including about 116,000 out of the 139,000 pupils enrolled. Its main purpose was to establish the incidence for age, grade, sex and type of school of the following defects: myopia, spinal curvature, nasal hemorrhages, headaches and nervous troubles.

Khlopine's data show that myopia is much more common in the upper grades than in the lower, in the larger cities than in the smaller, and in western than in eastern Russia. Spinal curvature increases about 50 per cent, between the first and the last school grade. Between the first and the seventh grade headaches double in frequency while nervous troubles increase nearly fivefold. Nasal hemorrhages, which are thought by some to be associated with the circulatory changes in the head which result from the act of reading, were twice as common in the classical schools, with their heavier demands for reading, as in the technical schools.

We can not here enter into a critical discussion of the above investigations. It is well to emphasize, however, that such studies have to deal with exceedingly complex factors whose respective influences are hard to separate. At the same time, the problems are very challenging to the biologist and physiologist as well as to the school hygienist, and are probably capable of being refined in such a way as to yield more positive results than we have yet had on this aspect of human efficiency.