ALBUMINCRIA OF THE NEWBORN The earliest statements to the effect that the urine of the newborn might be albuminous were the result of examinations of the bladder content in still-born children, or in those who perished shortly' after delivery. But after Martin and Ruge had shown that urine originally free from albumin became albuminous after remaining in the bladder for 1S hours, previous examinations could no longer be considered conclusive as to the condition of the urine in living subjects. The question whether albuminuria in the newborn is a physiological process was again agitated as a result of the examinations of Dohrn upon living subjects. This author found in 62 per cent. of his cases that the urine discharged immediately after delivery was free front albumin, He found in 32 per cent. distinct traces; in 9 per cent. considerable traces; and in 6 per eent. abundant quantities of albumin. Thereafter the investigations into the presence of albumin in the newborn became more numerous from the combined work of German, French, and English sci entists. Flensburg's Table gives a summary of the work of the Germans.
From this table we learn that in a large percentage of newborn children albumin appears in the urine after delivery, and that it persists for a longer or shorter time but under normal eonditions it generally disappears by the tenth day. The French scientists arrived at differ ent conclusions. Parrot and Robin declare that they never have been able to prove, even with the most delicate methods of exaniination, the presence of even traces of albumin in the healthy newborn ("chez les Enfants bien portants"). Throughout the French literature the opinion prevails that tbe investigations which showed the occurrence of albuminuria in the first years of life, do not add anything to the physiology of the urinary- excretion in the newborn.
It may- now be interesting to consider the theories which have been advanced to explain the oceurrenee of this allmminuria. We find men tioned as causes:—"Funetional ditturbance appearing after delivery, with resulting renal hyperaunia; defeetive development of the glomeruli in the newborn; albuminuria in the mother; and infarctions of uric acid." There seems no doubt that, among these causes, urie acid infarction has some significance, because its coincidence has been shown by- numerous examinations. But on the other hand, it should not be forgotten that albumin has often been found where there was no infarc tion: often enough indeed to disprove the general validity- of this par allelism, in whieh Hofmeier was inelined to believe.
Infarction, according to Flensburg, induces the appearanee albu min by mechanical irritation. But we may readily conceive a chemical irritation, such as appears in adults as the result of high concentration and an increased excretion of uric acid. Casts may also be explained by infarction producing mechanical and chemical irritation.
We arc indebted to Ribbert for the study of the anatomical con ditions which are the basis of the albuminuria of the newborn. Accord
ing to this author the epithelium of the urinary tracts does not play an essential red.e. He believes that the whole of the albumin is derived from the glomeruli, because he was able to prove coagulation in their capsules in the newborn by fixing with alcohol and boiling water. Ilow ever, according to Ribbert, not only is the albuminuria of the newborn a continuation of the embryonic process (it is well-known that the glom eruli of the fcetus excrete a permanently albuminous fluid), but the increased metabolism of the infancy he regards as one of the most impor tant causes of albuminuria.
In our efforts to explain the albuminuria of the newborn we are still far from escaping, mere hypotheses, and as long as this is true all dis cussions to determine whether or not the albuminuria is a physiological process Or not are of little value. Czerny and Keller believe that it is absolutely necessary to a profitable discussion of this point that the relations between nutrition and processes in the gastro-intestinal tract on the one hand, and the alburninuria on the other should have first been studied.
To-clay., this much is certain—and it has a practical value—albumi nuria in the first days of life is of no serious significance, nor is its ana tomical substratum by- any means an inflammatory process in the kidney. It is only when albuminuria persists and can be detected by the ordinary tests after the tenth day that we have to do with a condi tion which really is normal.
It seems to be necessary to enter briefly into the discussion of the quality and quantity of the excreted albumin. Flensburg identified the albumin with nucleo-albumin, and added these words:—"This albumin body has not yet been proven to exist in the blood, but only in the urinary tracts and in the kidney substance." 'What has already been said relieves me of the. necessity of emphasizing the fact that Flensburg's remarks not only as to the genesis, but as to the nature of this albumin body, are purely hypothetical. It no more admits of proof than the statement made many years ago, and recently revived, that this albumin is not blood-albumin at all, but niticin from the urinary tracts, and that therefore we have no right whatever to speak of an albuminuria, but only- of a mucinuria. In refutation of this, I am able to state as the result of a great many examinations of my own, that the albumin body preeipitated by aeetie acid is almost always to be found in the urine of the newborn, but that in addition there is present in most cases an albumin which we may designate as either albumin or globulin according to the limits of precipitation. Accolding to my experience the quantity of albumin excreted was from 0.2 per cent. to 2.0 per cent.; the proportion of albluninoid precipitated by acetic acid to the total albumin varying.