APPENDIX TO CHAPTER I AMINES 133 



ever, it seems generally impossible to isolate more of the amine than 

 Ackermann obtained and the yield is often very much less. The 

 mode of action of one and the same organism seems to depend on 

 conditions which areas yet imperfectly understood, so that this method 

 is rather uncertain. 



Mellanby and Twort [1912] have isolated a bacillus of the 

 typhoid-coli group from the intestine of various mammals (from the 

 duodenum downwards) which is capable of decarboxylating histidine. 

 The best yields of the amine were obtained by inoculating histidine 

 solutions with adequate quantities of a vigorous twenty-four hours' 

 culture of the organism on glycerine-agar and incubating for one week 

 at 37. The solutions contained histidine I per cent., ammonium 

 tartrate I per cent, dipotassium phosphate cri per cent., magnesium 

 sulphate 0*02 per cent., calcium chloride O'Oi per cent., but no peptone. 

 Solutions containing O'l per cent, histidine give a better yield. See 

 also patents by Hoffmann, La Roche & Co. [1912] and papers by 

 Berthelot and Bertrand [1912, i, 2; 1913, I, 2] and by Bertrand and 

 Berthelot [1913] describing the isolation of Bacillus aminophilus intes- 

 tinalts, a Gram-negative capsulated organism, resembling B. lactis 

 aerogenes and the bacillus of Friedlander, but differing from these in 

 its great power of decarboxylating amino-acids. For isolation of the 

 organism they used o -2 grm. K 2 SO 4 ,O'2grm. MgSO 4 ,O'5 grm. K 2 HPO 4 , 

 0-25 grm. KNO 3) 0*02 grm. CaCl 2 and 1-5 grm. histidine hydrochloride 

 per litre. 



To isolate /9-iminazolyl-ethylamine when pure histidine has been 

 submitted to putrefaction, it is hardly necessary to precipitate with 

 phosphotungstic acid. Instead one can precipitate at once with picric 

 acid, having removed ammonia, and recrystallise the picrate. For the 

 isolation of the base from complex mixtures such as ergot, it is neces- 

 sary to fractionate with silver nitrate and baryta. The base is then 

 found in the histidine fraction. Its hydrochloride is conveniently 

 separated from inorganic salts by extraction with methyl alcohol. 



Salts of $-iminazolyl-ethylamine. The dihydrochloride, C 5 H 9 N 3 . 

 2HC1, is extremely soluble in water and sparingly soluble in ethyl 

 alcohol; it crystallises in prisms; m.p. 240. The dihydrobromide\&s 

 similar solubilities and forms stout prisms sintering at 265 and 

 melting at 284 (corr.). The acid phosphate, C 5 H 9 N 3 . 2H 3 PO 4 , is some- 

 what less soluble in water and crystallises very well ; it decomposes 

 indefinitely at 120-140. 



Ihzplatinichloride, C 5 H 9 N 3 . H 2 PtCl 6 , orange coloured prisms readily 

 soluble in hot water and hardly at all in alcohol, blackens and de- 



