256 INTERNAL SECRETION 



urohypertensin. But it must be remembered that the accounts both 

 of " urohypertensin " and of " urohypotensin," which is described 

 by the same authors, are in need of further confirmation. As 

 Comessatti showed, Ehrmann's reaction is useless as a test for 

 adrenalin in the urine. Whether or not the substance, which 

 Schur found by his chemical test to be present in normal human 

 urine, is identical with adrenalin, is a question which must for 

 the present remain unanswered. 



As previously stated, according to Falta and Ivcovic, 

 adrenalin, when introduced in large doses into the stomach, does 

 not attain to specific activity within the organism, but is excreted 

 in the urine. 



More important than its excretion by \vay of the kidneys, is 

 the manner in which adrenalin becomes destroyed within the 

 organism itself. Such destruction takes place, in the first instance, 

 in the blood and depends principally upon the alkalinity of the 

 latter. According to Embden and v. Fiirth, .1 grm. of hydro- 

 chloric suprarenin, if added to 200 c.cm. of defibrinated ox-blood 

 and continuously aerated at incubation temperature, disappears, 

 almost entirely in two hours. In " laked " blood, the disappear- 

 ance is even more rapid. A .1 per cent, soda solution has a more 

 energetic action than either blood or blood-serum. The relatively 

 lower activity of the blood is probably due to the fact that a 

 proportion of the alkaline contents of the blood is fixed. 



That the degree of the alkalinity of the blood plays an im- 

 portant part in the disappearance of adrenalin, is shown by 

 Kretschmer's experiments. By means of the intravenous injec- 

 tion of acids, he succeeded in prolonging to five or six times the 

 normal, the hypertension produced by adrenalin in rabbits. The 

 addition of acid-ions, inhibits the destructive action of the 

 hydroxyl-ions in the blood and the tissues, upon the adrenalin. 



Another factor in the destruction of adrenalin is the liability 

 of the adrenalin molecule to oxidation, more especially in alkaline 

 solutions. 



Langlois believed that the destruction of adrenalin was princi- 

 pally oxidative. He and Athanasiu found that the vaso-contractor 

 constituent of suprarenal extract may be rendered negative by 

 means of ozonized air (aeration) and by the oxidase of crabs' 

 blood. The fact that, in cold-blooded animals, the vaso-constrictor 

 effect may be shortened by warming and lengthened by cooling, is 

 accounted for, in Langlois's view, by the dependence of processes 

 of oxidation upon temperature. He believes that all the tissues, 

 and especially those of the liver, intestine and, to a certain small 

 extent, the lungs, take part in the oxidative destruction of 

 adrenalin. He bases his conclusion chiefly upon the results of 

 experiments in which solutions of suprarenal extract were rapidly 

 rendered inactive by the addition of the fresh pounded liver and 

 intestine of rabbits; while, on the other hand, the artificial circu- 



