Mery and other French authors agree with Froehlich in distinguish ing between a renal form of intermittent and functional albuminuria. The renal form is said to be a deuteropathic manifestation of acute nephritis and to be carefully distinguished from chronic nephritis. Mery's definition of this form is: "The symptoms of chronic nephritis are absent, but bloatedness, headache, and tense pulse are present." According to this author the functional form is intermittent from the beginning; the complaints of patients are of a general nature; at the same time there are frequently vasomotor anomalies; exaggerated exercise and nervous excitement increase the albuminous excretion. Mery emphasizes the urological cycle of Teissier as a characteristic peculiarity of the functional form: "The manifestations consist in the fact that in the daily urine there is successive or increased secretion of pigments, albumin and uric acid, which daily recurs in definite cycles." From an etiological point of view Mary divides the functional form as follows: the gout-threatening form, which is the most frequent and important and mostly affects neurasthenic, over-fed individuals; the hepatogenous forin, which is often associated with acholuric icterus; the digestive form, which is characterized by the excretion of (nutritive) proteids during the digestive period exclusively; the mechanical form, which may be of an orthotic or a hypostatic type; and the pretuberculous form.
It will be seen from the foregoing that the varying conception of orthotic alburninuria is not only exemplified by the clescription of the symptomatology, but also in attempts at its explanation. Thus, the renal form of the French evidently comprises only forms of terminating nephritis, and it may have been just this kind of cases in which pronounced involvement of the heart or vascular system has been observed.
The pathogenesis of orthotic albuminuria can only be thoroughly understood if two preliminary questions can be satisfactorily- answered. They are: 1. How does it happen that anatomically- intact kidneys secrete albumin? 2. How can it happen that the factor causing the albuminous secretion is only active in the erect position of the body? Let us first examine in how far these two questions have already been answered by the theories described and by those which will still have to be described.
Albuminous excretion as such may be occasioned by albuminous substances coursing in the blood which cannot be assimilated by the organic cells. Von Noorden, among others, at the time seriously dis cussed the possibility whether the pathogenesis of orthotic albuminuria might be thus explained. The theory could be supported by the behavior of the excreted albumin, since it showed the property of being precipi table, wholly or in part, by acetic acid. At any rate, there is no orthotic albuminuria without the excretion of albuminous bodies that can be precipitated by acetic acid. Since. how-ever, this property characterizes but very imperfectly the nature of the protein substances it is clear that no conclusion can as yet, be drawn from it in regard to the quality of the excreted albumin, and no discussion can be profitable as to whether it is assimilable or not. Besides, the fact of insufficient assimilability would
only explain the alburninuria, but not the phenomenon of orthosis.
It will be necessary, therefore, to look for other explanations.
Von Leubc's idea of dividing the human race into individuals with permeable, relatively and absolutely impermeable renal filters, is of little value, since the assumption that the urinary substances are secreted by a filtration process is no longer tenable. True, Runenberg has shown that under low pressure proteid solutions can be better filtered titan under high and is inclined to refer albuminuria to reduced blood pres sure. Heidenhain has pointed out that experiments made with dead membranes are no criterion for processes going on in the living renal parenchyma: besides, he gave Rultenberg's experiments a different int erpret at ion.
It would materially advance our knowledge of this theoretically and practically interesting form of albuminuria, if it could be decided whether the renal epithelia become permeable to the protein bodies of the blood, or whether protein substances are seereted from the cellular structures into the urine. It is assumed that toxic injury to the renal epithelia or kinking of the renal artery leads to excretion of nueleo albumin from the nuclear substances of the renal epithelia. True, the albumin excreted in orthotic albuminuria shares with nucleo-albunain the property of being precipitable by acetic acid, but, so far as present investigations admit of a conclusion, it contains no pho.sphorus. It may, therefore, be permissible to assume that the "functional" lesion of the renal epithelia which must always be present in albuminuria, has ren dered the epithelia permeable to the proteid of the blood; and since the epithelia of the kidney pre-eminently show this peculiarity in circulatory disturbanees, the idea suggests itself that the latter, or vasomotor insufficiency, are responsible for orthotic albuminuria.
lidel was the first to make this suggestion, but he failed to explain what peculiarities of the cardiac and vascular functions will cause albu minuria when changing the horizontal to the erect position. He pointed out, however, that factors favoring the disappearance of albuminuria also lead to changes in the pulse, which in volume and frequency was more re sistant to certain demands in non-albuminous than in albuminous periods. I have pointed out the great frequency of vasomotor phenomena in a great number of orthotic children and differentiated between an angiospastic and erethic type, according to the preponderance of the vascular spasm in the clinical picture. Martius observed cardiac dilatation and weakness in a very large number of patients, although other investigators noticed considerably fewer such eases or none at all. Increasing experi ence with orthotic albuminuria tends to support the opinion that this affection is connected with the function of the circulation. Experi ments made by Erlanger and Hooker, as well as by Frank, cxplain this connection.