94 THE SIMPLER NATURAL BASES 



the same residual load of adrenalin, 2 or 3 mg. , as would be found in 

 any other individual dying similarly without kidney disease. 



The supra-renal gland of mammals is made up by the close asso- 

 ciation of two tissues, the cortex and the medulla, corresponding 

 respectively to the inter-renal and adrenal tissues of the lower verte- 

 brates, in which the two kinds of tissue are less closely associated. In 

 fishes they occur separately. The medullary substance, also called 

 chromophil or chromafrin on account of its being stained brown by 

 chromates, alone contains adrenaline (see for example Gaskell 

 [1912]). This tissue is also present in the paraganglia, associated 

 with the sympathetic system of mammals, including the carotid gland, 

 and the fcetal organs described by Zuckerkandl. An extract of these 

 paraganglia has been shown to possess the physiological action of 

 adrenaline. Further details concerning the distribution of chromo- 

 phil tissue are contained in Vincent's article in the " Ergebnisse der 

 Physiologic" [1910, under general references to Ch. VI] and Biedl's 

 " Innere Sekretion " [1913, general references to Ch. VI]. Recently 

 the remarkable discovery has been made by Abel and Macht [1911, 

 1912] that adrenaline occurs in the secretion of the so-called "par- 

 otid gland" (on the skin behind the ear) of a tropical toad, Bufo agua. 

 The amount of adrenaline in the dried venom is as much as 5 per cent. ; 

 the substance is chemically and physiologically identical with the 

 adrenaline from the supra-renal gland of mammals ; in particular the 

 rotation was found to be [a] D at 20 =--51 -30, in perfect agreement 

 with the value given by Flacher (-51 '40, see above). 



Bufo agua is not immune to its own poison and reacts to 

 adrenaline in the same way as the frog. As might be expected the 

 tissue of the poison gland gives an intense chromophil reaction with 

 chromic acid. According to Gunn [1911] cobra venom injected 

 intravenously has a pressor action like that of adrenaline. 



Adrenaline is continuously secreted by the supra-renal gland and 

 is therefore present in appreciable quantity in the blood of the supra- 

 renal vein; Cybulski [1895] first demonstrated the pressor action of 

 the blood from this vein, in which the adrenaline concentration is 

 of the order of I : 1,000,000. Adrenaline must therefore also be 

 present in the blood of the general circulation, but the amount is so 

 small that it cannot be demonstrated with certainty (O'Connor 

 [1912, I], Stewart [1912]). Adrenaline has been said to occur in 

 the urine in nephritis, but the evidence is doubtful, and this also 

 applies to pathological sera. 



