ADRENALIN. 379 



The synthetically prepared adrenalin is optically inactive d-Z-adrenalin, 

 while that from the adrenals is optically active Z-adrenalin. FLACHER has 

 divided the racemic adrenalin into the two optically active components, 

 and the identity of the so-obtained synthetical adrenalin with the natural 

 has been shown by ABDERHALDEN and FR. MuLLER. 1 These last inves- 

 tigators also found that the /-adrenalin had at least 15 times as strong 

 an action upon the blood-pressure as the d-adrenalin, and later ABDER- 

 HALDEN with THIES and SLAVU found that the /-adrenalin had also in 

 other respects a much stronger action than d-adrenalin. 



Adrenalin crystallizes in masses of needles or rhombic leaves. It is 

 soluble in water, and can be precipitated from its solution by ammonia 

 as a crystalline substance. Its aqueous solution containing hydrochloric 

 acid is levorotatory: (a) D = 50.72 (ABDERHALDEN and GUGGENHEIM 2 ). 

 On heating adrenalin it turns yellowish-brown at about 205 and decom- 

 poses at about 218 C. Its solution turns emerald green with ferric chlor- 

 ide in acid solution and carmine red in alkaline solution. Adrenalin 

 reduces FEHLING'S solution and ammoniacal silver solution. 



Among the reactions for adrenalin in solution we must especially 

 mention the red coloration which is obtained on the addition of an oxidizing 

 medium such as iodine or bi-iodate and dilute phosphoric acid and warm- 

 ing (FRANKEL and ALLERS), or of mercuric chloride in the presence of a 

 catalyst such as the lime salts in tap-water (COMESATTI). These reactions 

 are extremely delicate, 1 : 1000000-2000000. A still more delicate reaction 

 (1:5000000) is the one suggested by Ewms, 3 namely a characteristic 

 red coloration is obtained on adding a 0.1 per cent solution of potassium 

 persulphate and warming gently in a boiling water-bath. 



As above stated, it has been considered for some time that the color 

 of the skin in ADDISON'S disease was connected with the adrenals or their 

 chromogen. We know nothing positive in regard to this relation, 

 but it is nevertheless of interest that pigments, and finally melanins or 

 at least dark-brown substances, can be produced from adrenalin by the 

 action of enzymes. NEUBERG has brought about such melanin forma- 

 tion by the extract from the metastases of a melanoma of the adrenals 

 and also with the extract of the ink-sac of the sepia, and ABDERHALDEN 

 and GUGGENHEIM 4 with tyrosinase. This would indicate a close relation 



' 1 Flacher, Zeitschr. f. physiol. Chem., 58; Abderhalden and Franz Miiller, ibid. 

 58; with Thies, ibid., 59; with Slavu, ibid., 59; with Kautsch and Miiller, ibid., 61 and 

 62; see also Frohlich, Centralbl. f. physiol., 23 and Waterman, Zeitschr. f. physiol. 

 Chem., 63. 



2 Zeitschr. f. physiol. Chem., 57. 



3 Frankel and Allers, Bioch. Zeitschr., 18; Comesatti, Munch, med. Wochenschr. 

 1908 and Physiol. Centralbl., 23; Ewins, Journ. of Physiol., 40. 



4 Neuberg, Bioch. Zeitschr., 8; Abderhalden and Guggenheim, Zeitschr. f. physiol. 

 Chem., 57. 



