It must be remembered that short-sight tends to increase during the early, especially the school, years of life, and that hygienic treatment, good light, good type, and avoidance of stooping are important for its prevention.
For the chemistry of copper and its compounds see the references in the article Chemistry: Inorganic. Toxicologic and hygienic aspects are treated in Tschirsch's Das Kupfer vom Standpunkt der gerichtlichen Chemie, Toxikologie and Hygiene (Stuttgart, 1893).
The improvement which has taken place in the general health of the inhabitants of cities during recent years, concurrent with hygienic legislation, is ample proof of the above assertions.
The great difference between the serial rank occupied in the respective lists by Russia, Servia and Galicia, with remarkably high rates of natural growth, as well as that found in the case of most of the other countries in question, shows that this factor is by no means a trustworthy guide in the estimate of hygienic balance.
A plentiful supply of hot water is a necessity in every house for domestic and hygienic purposes.
Although there is no objection to this product from a purely hygienic point of view, it is not natural wine, and the products present in the must other than sugar and acid are by this process seriously affected.
In the stable a horse should always be provided with rock salt, and water to drink at will by means of some such stall fixture as the Mundt hygienic water-supply fittings.
The hygienic conditions should be such as to reduce the strain to a minimum.
Farther on are the chemical and the physical laboratories and the Hygienic Institute.
The hygienic improvement effected by these changes, and by a new and excellent water supply, is shown by the mortality averages-40 4 per thousand in 1871-1875,30.4 per thousand in 1881-1885, and 20.5 per thousand in 1903-1904.