Langstein and .11eyer have studied qualitative disturbances in the course of the processes of oxidation in older children, investigating the excretion of acetone bodies in febrile diseases and in conditions of inanition, especially where there was carbohydrate insufficiency,. From thcse experiments one fact appears characteristic for childhood that the disturbance: of the intermediary metabolism which lead to the excretion of acetone bodies, proceed from the same causes as in adult life; but occur very much more readily in childhood. A further peculiarity of infancy, according to these authors, is that the pathological increase in excretion of acetone takes place mainly through the expired air, and not as in adult life through the urine. Missy found in his experiments, which are not yet published, that the excretion of acetone did not in variably follow this rule. The condition of cyclic vomiting with fever without organic disease (acetone vomiting) has been much discussed of late in French literature. In this condition acetone is perhaps the specific ag,ent, it at least appears in large amount in the urine; on the other hand the diagnostic importance once ascribed to I.egal's test for the differentiation of etiologically- different throat inflammations has not been confirmed. The meaning of acetone bodies in the 'metab olism of infancy will be mentioned in the following pages.
Let us now leave the subject of the essential intermediary' metab olism and consider the fate of the mineral salts, which are combined with the food stuffs and other constituents of the body, are involved in their disassimilation, and are excreted through the urine. One fact stands forth preeminently in this line of work, which has not only guided the investigations of pathological metabolism, but has especial importance at the present time when we consider the metabolism of salts. It also has a practical value for the study and successful management of the diet of sick infants. Keller found in the year 1894 that the urine of sick infants contained remarkably large amounts of ammonia, so much that in extreme cases the ammonia-nitrogen at times equalled nearly 50 per cent. of the total nitrogen excretion, or (more tersely expressed) that the so-called aminonia coefficient could rise almost to 50.
The most probable explanation for this remarkable fact was given by Thiemich, who succeeded in demonstrating an advanced degree of degeneration of the liver in infants, and in some children who had excreted during life these very large amounts of anunonia, whereby the possibility was suggested that the cause of the increased excretion of ammonia lay in the diminished power of the liver to form urea. Direct investigations, however, proved this supposition to be incorrect and showed that even very sick infants were able to transform the ammonia salts introduced, into urea. A large series of observations, and the well
known property of ammonia—to appear in the urine in the company of aCidS,—led. to this conchtsion: increase in excretion of ammonia could be brought about by increase in excretion of acid products of metabolism. Dijmanns von der Bergh proved by the use of the so called Schroder-Munzer criterium that this view was correct, since by the administration of alkali the previously' high excretion of ammonia could be reduced to nothing. But whence canie the quantities of acid, for whose saturation the organism is forced to manufacture such enorm ous quantities of ammonia, since the existing supply of alkali at the disposal of the body would by- no means suffice for this purpose? A large number of experiments were carried out at the Breslau Clinic to decide this question, as to the influence exerted by the diet upon the excretion of ammonia in sick infants. They led to this definite result, that the administration of fat brings about high excretion of ammonia, whereas the removal of fat from the diet causes its disappearance. The question still remained unsolved as to the nature and origin of the acids in question. The view- was held for a long time by the pupils of the Breslau School, that analogous to diabetes there was an increased or abnormal formation of organic acids in the intestines, or in the inter mediary metabolism, and that the cause of their incomplete combustion must be ascribed in part at least to a diminution of the normal oxidiz ing powers of the organism.
Steinitz's studies of the metabolism of alkalies showed that a genuine acidosis of this type does not ordinarily occur, and that the reason why increased fat in the diet led to greater excretion of ammonia by the kidneys, was altogether different.
Steinitz showed that the result of the introduction of definite amounts of fat into the intestines was increased formation of alkaline soaps; the alkalies required are thus prevented from reaching their normal destination (in the body); ammonia must be supplied to neu tralize the usual inorganic aeid end-products of metabolism, and there fore appears in the urine in increased quantity, whereas the alkalies are excreted in the feces and sometimes in such quantities that the balance of alkali in the body may remain constantly' negative.
A second cause for the increased ammonia is the greater absorption of phosphoric acid from a diet rich in fat. Even when considerable quantities of lime-soaps are formed in the intestines. an increased ex cretion of lime through the intestines does not follow-, but the formation of calcium phosphate (which is, absorbed with difficulty) does not apparently: take place to the same degree. A greater amount of phos phoric acid is absorbed under these conditions, possibly already- com bined with ammonia, in wlaieh form it is excreted in the urine (Freund).