200 THE DUCTLESS GLANDS 



(" Bufagiii ") in the venoin. The crude poison of the toad 

 contains nearly 7 per cent, of adrenin. 



N. The Origin of Adrenin in the Body 



Nothing is definitely known of the nature of the parent 

 substance from which adrenin is derived. It has been sup- 

 posed that the waste products of muscular metabolism are 

 converted into adrenin. This view appears to be based upon 

 results obtained by Boruttau and Langlois upon frogs whose 

 adrenal bodies had been removed, and which were benefited 

 by injection of adrenal extracts. The theory would imply the 

 formation of adrenin from some such substance as creatin. 

 This is the least probable of the three suggestions. 



Abelous, Soulie, and Toujan are of the opinion that adrenin 

 is manufactured in the cortex from tryptophane. 



Halle has suggested that one of the substances from which 

 adrenin is formed in the organism may be tyrosin, and has 

 brought forward some evidence for this view. He points out 

 that adrenin might be produced from tyrosin by (1) introduc- 

 tion of a hydroxyl group into the benzene ring ; (2) elimination 

 of C0 2 from an amino-acid to form an amine ; (3) the methyla- 

 tion of nitrogen ; (4) the introduction of a hydroxyl group into 

 an aliphatic chain. He states that when two portions of 

 emulsion of fresh ox or pig adrenal were taken, to one of them 

 tyrosin being added, both being kept under aseptic conditions 

 for six days in an incubator, the sample containing the tyrosin 

 was found to have from 14 to 33 per cent, more adrenin than 

 the control. 



Gessard imagines a relationship between tyrosin and adrenin, 

 because both substances become pigmented in a similar manner 

 by the action of tyrosinase. 



The theoretical speculations of Halle would appear to be 

 open to criticism, as pointed out by Ewins and Laidlaw. 

 Moreover, the last-named observers were unable to confirm 

 Halle's experimental results. The matter is by no means 

 settled, and, although the hypothesis that adrenin may be 

 derived from tyrosin is not supported by the evidence before 

 us, yet it would be rash to dismiss this substance from con- 

 sideration as one of the possible precursors of adrenin in the 

 animal economy. 



