The greater part of the glucose in the economy, in health, is introduced with the food, either in its own form or as other carbohydrates, which by digestion are converted into glucose; a certain quantity is also produced in the liver at the expense of glycogen - a formation which continues for some time after death. In some forms of diabetes, the production of glucose in the liver is greatly increased. The quantity of sugar normally existing in the blood varies from 0.81 to 1.231 parts per thousand; in diabetes it rises as high as 5.8 parts per thousand.

*Lyon Med.

†Prof. Charles F. Stillman.

Under normal conditions, and with food not rich in starch and saccharine materials, the quantity of sugar eliminated as such, is exceedingly small - so small, indeed, that some observers have contested the fact of any being eliminated in health. It is oxidized in the body, and the ultimate products of such oxidation are eliminated as carbonic acid and water. Whether or not intermediate products are formed, is still uncertain; the probability being that they are. The oxidation of sugar is impeded in diabetes.

So long as the quantity of glucose in the blood remains at or below the normal percentage, it is not eliminated in the urine in quantities appreciable by the common tests; when, however, the amount of glucose in the blood surpasses this limit from any cause, the urine becomes saccharine to an extent proportionate with the increase of glucose in the circulating fluids. The causes which may bring about such an increase are numerous and varied; many of them are entirely consistent with health, and the mere presence of increased quantities of sugar in the urine is no proof, taken by itself, of the existence of diabetes.

In true diabetes, the elimination of sugar by the urine is constant, unless arrested by regulation of the diet, and not temporary, as in many other conditions. The quantity of urine is increased, sometimes enormously, and the specific gravity is high; the elimination of urea is increased absolutely. The quantity of sugar eliminated varies from 6.4 ounces to 12, and even 45 ounces in twenty-four hours. During the night, less sugar is voided than during the day; the hourly elimination increases after meals, reaching its maximum in four hours, in proportion to the amount of food taken. It is, therefore, obvious that, in order to make quantitative estimates of sugar of any clinical value, it is necessary to take the sample from the mixed urine of the whole twenty-four hours *