Reducing Substances.—It is often claimed that the urine of the young, especially that of infants has a greater power of reducing the metallic oxide than is the case with adults. We cannot, however, draw any far reaching conclusions from this, because in these investigations the line between healthy and sick children has not been drawn with sufficient clearness. The statements in regard to the nature of the reducing substances are extremely few and very unreliable. Since the proofs offered of reduction are remarkably ambiguous, it should be insisted that the presence of sugar should first have been established by the osazon test, before we can accept the results of a reduction experi ment. After warming the urine with muriatie plienyl-hydrazin and sodium aeetate for half an hour in boiling water, a precipitation consist ing of yellow needles (osazon) will be found immediately, or else after cooling if sugar is present.
Binct declares that every normal infant excretes traees of sugar (if the trace is exceedingly small, the osazon test will be negative with diluted urine, and will only be obtained if tbe urine is concentrated. Therefore if crystals are formed in untreated urine, we may suspect the presence of pathological eonditions). Sorne writers have observed a greater tendency to glycosuria in newborn babes, but it is not certain that these observations were made in healthy infants. Stcinitz and Langstein have been able to demonstrate that breast-fed babies with gastro-intestinal disturbance excreted in the urine both milk-sugar ancl one of its derivatives, galaetose. Geelmuyden declares that lie found in the urine of diabetic children, in addition to glucose, another kind of sugar (paidose), which was optically. inactive. After boiling with acid, these separated out a substance which deflected the polarized beam to the right, and left osazon, with a melting point of 130-175° C. (266 347° F.).
Oxalic acid, as has been shown by the investigations of Parker Sedgwick at Heubner's Clinic, seems to be excreted in absolutely larger quantities by children than by- adults. It must be recognized, however, that the mere finding of a sediment of oxalate crystals does not justify the conclusion that there is a greater excretion of oxalic acid.
Diazo Reaction.—Authorities are in accord that in most eases of measles, Ehrlich's diazo reaction is eonspieuously positive, although it is true, as stated by Ottfried Muller, that this is not an early symp tom, but only makes its appearanee after the exanthem has come out. In cases of scarlet fever it was observed frequently- by some authors, but rarely by others. Nikos Kephallinos found the reaction positive during the first week in 92 per cent. of the eases of typhoid in children examined by him. In purulent cerebrospinal meningitis he found it negative as often as positive, and he reports that he never obtained it in cases of whooping-cough, erysipelas, mumps, gonorrlweal rheuma tism, sepsis, influenza, diphtheria, or syphilis. The diazo reaction is approximately the same in infantile tuberculosis as in the adult form.
It is positiy-e in most cases of tuberculosis of the lungs, and of miliary tuberculosis (general). It is only exceptionally found in tuberculosis of the bones and skin, but almost always in tuberculous pleurisy. It iS uncertain in meningitis, and in tuberculous peritonitis. "True scrofu losis" is never attended by the diazo reaction, but it is noteworthy that the reaction is strongly positive in a group of tuberculous eondi tions of the lymph-nodes, which were classed under the heading of pseudoleuktemia. It is therefore possible that the diazo reaction tnay be of some importance in the diagnosis of tuberculosis, where other clinical evidences of its presence are laeking. Moreover, the reaction was found in no small percentage of eases of lobar pneumonia, but it was nearly always absent in rachitis, in nervous diseases, and in diseases of the digestive, the eirculatory, and the genito-urinary systems.
The nature of the diazo body is unknown: it is still even a question whether it is nitrogenous or non-nitrogenous, although, it is true, that the latest, though still unconfirmed investigations, declare that it is a highly complex derivative of albumin. My own opinion inclines to the theory that the diazo body is not a single substance at all, but that in different diseases different substances may produce the reaction. Kephallinos rentinds us of the fact that the reaction 'nay even be lini tated by the passage of drugs through the urine, and he mentions among the substances capable of producting changes in the color shades, creo sote and its derivatives, carbolic acid, thyinol, opium, cascara sagrada, and hydrastis. The same may be said of rhubarb and of santonin, which induce the excretion of a pigment body, which turns red in alka line solutions. It is said that tannin, and tannin-containing substances, when added to diazo-positive urine, will prevent the reaction.
Albuinosuria and Peptonuria.—In spite of the elaborate studies on the exeretion of albumose and peptone, we cannot obtain a clear idea of the conditions under which they are found in infancy. This mueh is certain, that in nearly all infectious processes, especially scarlet fever and measles, albumosuria is present, but how far this is the result of the specific infection, how far it depends upon complicating condi tions, cannot be discovered from reading the literature, and from this point of view, the whole subject deserves a new study. Siegert states that he has repeatedly observed the excretion of large amounts of albu mose in the late stages of scarlatina] nephritis, and he describes the appearance of albumose as a Favorable prognostic symptom of speedy recovery from the nephritis.
Toxicity of the ETrine.—This is said to be greater in infants than in those of adult age. It appears unnecessary to treat this matter in detail, because the theory of urinary toxicity, which has been advanced espe cially by French writers, will not bear strictly scientific criticism, because the method is not above suspicion.