10 THE SIMPLER NATURAL BASES 



The decarboxylation of amino-acids is not necessarily accompanied 

 by any obvious sign of bacterial action such as putrefactive odour ; 

 some of these amines occur in cheese and they have repeatedly been 

 obtained in fermentation experiments supposed to be sterile (Langstein, 

 Emerson, Lawrow ; see the section on putrescine and cadaverine). 

 The difficulties of ensuring sterility, particularly in autolysis, have 

 often been underestimated and have been emphasised by Schumm 

 [1905-6], Rothmann [1908], Kikkoji [1909], Salkowski [1909], Ohta 

 [1910], Harden and Maclean [1911], Beker [1913]. Chloroform 

 should not be used in conjunction with toluene, which dissolves the 

 chloroform from the aqueous layer. It is best, according to Schumm 

 and Kikkoji, to use water saturated with chloroform, or chloroform in 

 excess and to ensure continued saturation by means of stoppered bottles 

 and frequent shaking. Sterility tests should be made by smear. 



In the absence of bacteria, decarboxylation of amino-acids does not 

 occur; at least the corresponding primary amines are not found. 

 (Kutscher and Lohmann [1905], Schumm [1905-6], Bissegger and 

 Stegmann [1908], Schulze [1906], Kiesel [1911].) The occur- 

 rence of methylated bases such as tetramethyl putrescine and hordenine 

 in the higher plants perhaps implies the intermediate formation of 

 primary amines. Apart from putrefaction, putrescine and cadaverine 

 occur in cystinuric urine, agmatine in herring spawn and p-hydroxy- 

 phenyl-ethylamine in the salivary gland of Cephalopoda. It has further 

 been established that fresh fungi may contain amines resulting from the 

 decarboxylation of amino-acids or at any rate these amines are formed 

 by autolysis independently of bacterial action. The close relationship 

 between the fungi proper and bacteria makes this less surprising. 



Ergot, which has been examined more thoroughly than any other 

 fungus, contains p-hydroxy-phenyl-ethylamine, /3-iminazolyl-ethyl- 

 amine, putrescine, cadaverine, agmatine, and probably isoamylamine, and 

 owes much of its physiological action to the first two of these bases. It 

 is almost certain that they are to some extent present in fresh ergot, but 

 the amount is increased after death, probably by autolysis. Reuter 

 [1912] recently found putrescine in fresh specimens of Boletus edulis 

 and when this fungus was autolysed under sterile conditions, isoamyl- 

 amine, phenyl-ethylamine, probably p-hydroxy-phenyl-ethylamine and 

 possibly iminazolyl-ethylamine were formed in addition. Schenck 

 [1905, I] had previously obtained putrescine from autolysed yeast. 

 Reuter's experiments are of particular interest ; sterility tests showed 

 that bacteria were absent, and he concludes that fungi possess ferments 

 capable of decarboxylating amino-acids. 



