THE SUPRARENAL SYSTEM 263 



out nephritis, gives a positive Ehrmann reaction in about the 

 same percentage of cases ; though Comessati believes that the 

 Ehrmann test for adrenalin has a very limited scope when applied 

 to urine. 



As we have already pointed out, the mydriasis produced by 

 blood serum is not a conclusive test, that is to say, the reaction 

 is not confined to adrenalin. Bittorf, for instance, obtained 

 mydriasis with the serum of healthy persons after the exhibition 

 of salicylic preparations. That adrenalin is present in the serum 

 in chronic nephritis, is not confirmed by other biological tests. 

 Schlayer found that normal human serum produced marked con- 

 traction of portions of arteries removed from living oxen, while 

 the contractions produced in such portions of arteries by the 

 serum of nephritic persons were, in the greater number of cases, 

 much v. eaker. The significance of these negative findings is, 

 .however, very much modified by a later discovery of Schlayer's ; 

 to the effect, namely, that O. B. Meyer's test for adrenalin by 

 means of portions of arteries, is practicable with blood obtained 

 from animals of the same species only. In the case of blood from 

 animals of a different species, an increase in the adrenalin con- 

 tents has the effect of reducing the contractions. That chronic 

 nephritis is not associated with pathological adrenalincemia, is 

 well shown by the results which A. Fraenkel obtained, by the 

 most reliable of modern biological methods, with the uterus re- 

 moved from living rabbits. He found that, in chronic interstitial 

 nephritis with pathognomic hypertonicity, the variation in the 

 adrenalin contents was the same as in the blood of subjects with 

 sound kidneys. 



It must be borne in mind that, although a pathologically 

 increased adrenalinaemia, producing abnormal tonicity of the 

 vessels, would supply a satisfactory explanation of the hyper- 

 tonicity and cardiac hypertrophy in chronic renal disease, certain 

 proof of the existence of such a condition is, up to the present, 

 by no means forthcoming. Schur and Wiesel, who based their 

 experiments upon the assumption of a direct connection between 

 hypertension and adrenalinaemia, were compelled to abandon this 

 theory. They were unable invariably to produce mydriasis with 

 serum from nephritic patients, and they were unable to establish a 

 parallel between this reaction and a hypertonic condition.* 



* The possibility was recently suggested by v. Neusser and Wiesel that 

 a primary hyperplasia of the chromaffine system might lead to true 

 renal processes. Conditions which demand an increased consumption of 

 adrenalin, and of these the most important is forced muscular exertion, 

 may produce hypertrophic processes of the adrenal system. In such a 

 case the increased amount of adrenalin would cause a permanent vaso- 

 contraction, which might give rise to anatomical changes in the renal 

 vessels, which would prepare the way for the development of a nephrosis. 

 The authors lay stress upon the fact that, in cases of true contracted kidney, 

 the etiology of which is still obscure, hyperplasia of the chromaffine tissue 

 is invariably present. 



