1-10th inch objective. Tolles. 4 system. Immersion. 180° angular aperture.

1-16th inch. Tolles. 3 system. Immersion.

RESTORATIVES.

By J. R. UHLER, M.D.,

MARYLAND.

THE present may be described as the time of animal chemistry and for close imitations of nature secured by restorative remedies.

Restoratives are substances that supply to the system either pabulum or energy. They are naturally divided into foods proper, food preparers or ferments, and medicines; and belong either to the vegetable, animal, or mineral kingdom. Their actions are as various as their names; some building up the tissues almost mechanically, others only by putting energy into them. In systematic treatises, they are classed as foods, tonics, stimulants, ferments, nitrogenous, oily and sugary substances; but we prefer to call them restoratives simply because they can restore. Many have been in use since the earliest times, but restorative medicine proper owes its origin to the reaction against depletion and to the clinical observations of Drs. Todd, Bennett, Chambers, and a host of others. Like most other systems, it has had a struggle, but at present there is more danger from too ready acceptance and over-estimation than opposition.

Before restoratives can be properly used, we must be sure they are needed, and have some idea of the quantity. To secure this information, careful study of each individual case is required, and a knowledge of what the average man uses as food. The individual himself depends upon hunger and the feeling of satisfaction, due partly to the distension of the stomach, to regulate the quantity of aliment; but the comparative anatomist looks to the teeth and size of the organs, and speaks with more authority. The results of his observations seem to teach that the young require more nitrogenized material in proportion to their sizes than adults, and that the latter in their diet tables use more meat than the teeth call for. The physiologist and physician decide by more difficult and exact methods, such as 26a

( *409)

observation and analysis of milk, nature's own food, and of the income and outgo from the body, as shown by the secretions, excretions, etc. No random efforts will avail here, but systematic examinations of everything are required. Calibration of the stomach is essential to see if it will contain enough to keep up the man-power of the system, and test-trials of the digestive fluids are equally requisite. The average constitution of the human body also affords indications of what is needed to build up its various structures, since we know it is composed of so much water, nitrogenous, oily, and bony tissues, and have it in our power, through dilution and the microscope, to accurately count the number of the blood-globules, and determine the constituents of fluids. All this requires work, but not so much as formerly; and as more demands are made upon the chemist for clinical aids, simple and quick methods will be provided. Already a number of workers have taken the field, and present as the result many improvements.

Prof. Flint has praised Davy's plan for the clinical determination of urea, and another has been devised by two English chemists that is quite ingenious. They are somewhat unpleasant, and may soil the fingers on account of the mercurial or water bath that is essential, and this consideration has induced me to suggest several others. I do not wish at present to express any opinion upon their relative merits, but where a person possesses a sensitive balance, the one (Fig. 1) that I shall now mention