CHEMICAL BASIS <! T1IK ANIMAL iionv. 193 



in dilute ammonia. It crystallises in long brilliant white needles 

 which when kept under acidulated water an- often changed into 

 Ion;; glittering foursided prisms. 



Tins arid forms >alts of which that with barium crystalline- 

 readily and in a very characteristic triangular form. 



Apart from its crystalline form and tliat of its barium salt this 

 acid may he readily recognised by the following reaction. "When 

 heated on a water bath with hydrochloric acid and chlorate of 

 potash and evaporated to dryuess a reddi>h residue is obtained, 

 which turns at first to a brownish green on the addition of am- 

 monia, and finally to an emerald green. 1 



:J4. CRYSTALS OF BARIUM KTXI-RKNATE. (After Kulmc.) 



I'.v prolonged heating to 250 260 kynuivnic acid 

 carbonic anhydride and is converted into kynurin (o.\y hinolin ) 

 C 9 HN (OH), and when heated with /inc dust in a current of 

 hydro-en it is converted into chinolin C,H 6 N (OH) -f- H, = 

 C II N + ll-jO. These reactions throw considerable liu-ht on the 

 constitution of the acid. 2 



The amount of kynurenic acid in the urine is increased on the 

 :ion of isatin. a product of the oxidation of indigo. 3 Under 

 ordinary conditions its amount in this excretion is dependent upon 

 the nature of the food supplied to the animal, being greatest under 

 a pioteid diet, and is not related to the occurrence or absence of 

 putrefactive processes in the alimentary canal 4 



PhenoL C,H 6 .OH. Oxybenxol. (Gufcolio or pheny Ho acid.) 



This substance is formed, together with indol and skatol. dur- 

 ing the putrefactive decompo>ition ,,f protvids, more es|>criully in 

 prolonged putrefactive pancreatic digestions. 6 From these it may 



1 Jaffa', 7.1. f. ph,ii<J. ('/,. 1M. vn. (1SS2-." 



2 Kr - 1 5. 1 MI |l: ". s. 1673. 3/ono/<A. /. Ckem 

 15.1 ii ^57. 



s Ni ! I':iih. u. PHarm. R.I. in 



iinanii. '/.t f. iJu/tint. c/ lfm H,I. x. (issr,). s i:ti Hut . f . Haagen, Inaog - 



Iv.ni-sl. - Crntr.ill: I <l M- / H -.8.214.) 



Banmann. '/.< f } >h n.<ii. <'/,., IJ,j. - 50, MI .:.() Uri.-^-r. Ibid. 



Bd. in. (1879). S. 1.-J4. Odernmtt. Jn.f. prai-t. Chtm. Bd. xvm. (1878), S. S49. 



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