CHEMISTRY OF THE BLOOD.
1. Sugar.—That the percentage of sugar in the blood is greater than normal in every case of diabetes in which glycosuria is present has been already stated a number of times in this treatise. The glycosuria is the consequence of the In contrast to the normal amount of from 0.5 to 1.5 per mille, Pavy among others reports from 1.54 to 5.76 per mille, Seegen, in grave cases, from 2.3 to 4.8 per mille. The proportion is not always constant in each case, but varies, contrary to what obtains in the healthy organism, ac cording to the nature of the food ; the ingestion of carbohydrates increases it, the withdrawal of these substances diminishes it. In general there is an exact relation between the amount of sugar ex creted in the urine and that contained in the blood.
There is still much that is obscure in this field; further research into the reciprocal relations of diet, blood-sugar and urine-sugar is urgently needed and promises good results as regards our knowledge of diabetes. In the mean while these investigations are difficult of execution and uncertain in their results, for the reason that we possess no exact method by which we can estimate correctly the presence of small amounts of sugar in the blood.
2. Glycolitic Ferment. See page 54.
3. Water and Pel'ill«12ea Constituents. See page 91.
4. Fat.—In grave cases fat has quite often been found in the blood in such quantity that the serum was milky. I have convinced myself that this lipmmia was not connected with a previous ingestion of fat. What is the cause and what the. result of this transportation
of fat in the blood, and in general what the significance of the phe nomenon may be, are unknown. If the lipfemia becomes excessive it may result in lipuria, that is, in the passage of an extremely fine fat emulsion through the kidneys.
5. Alkalinity.—In patients who enjoy excellent general health the alkalinity of the blood is normal, but in those who are very much reduced in strength it is always diminished. The alkalinity has been found to be less than in any other disease in diabetics who had reached the stages of oxybutyric acid excretion, or who were already comatose. The alkaline value of the blood in such cases has been found to be only 40 milligrams of sodium hydrate (NaH0) per 100 grams of blood; the normal value is 350 to 400 milligrams. As has been shown above, the alkalinity of the blood is lowered by the pro duction of abnormal acids. For a discussion of this point and of the relation of a diminished alkalinity to coma, see page 95.
I would say here that I have come to regard with great distrust the methods hitherto employed for determining the degree of alka linity of the blood, and this on the ground of certain investigations which Lowy has most carefully carried out, at my suggestion, upon patients in the Charite Hospital in Berlin. Perhaps the near future will see a fundamental change in our views on this matter.