LECTURE XIII.] HISTORY OF CHEMISTRY. 257 



by Strecker, 10 made the halved formula more probable. Wurtz, 

 in the oxidation of propylene glycol, brought forward a 

 decisive reason for the latter view. 17 At the same time the 

 dibasic character of the acid also seemed to be confirmed, so 

 that Wurtz wrote : 



C 4 H,0 2 \o 



C 4 H 4 ) 



H,r 4 



Glycol . Glycollic acid [C - 6, O = 8]. 



Propylene glycol. Lactic acid. 



The reaction with phosphorus pentachloride, which yielded 

 the chloride C (; H 4 O 2 C1. 2 , (a substance that was converted by 



alcohol into chlorlactic ether, C 4 HJ 2 ' corresponding to 



Cl 



glycol-chlorhydrine) was a new argument in favour of this view, 

 whilst the vapour density of the chlorlactic ether justified the 

 molecular weight adopted. 18 



Kolbe regards lactic acid as monobasic, and calls it oxy- 

 propionic acid, assuming the same relation between it and 

 propionic acid as that between oxybenzoic acid and benzole 

 acid. 19 In the same way that Gerland was able to convert amido- 

 benzoic acid into oxybenzoic acid (by means of nitrous acid 20 ), 

 lactic acid can also be obtained from alanine. The latter and 

 glycocoll were to be regarded as amido-acids a view which 

 found new support upon the conversion of bromacetic acid 

 into glycocoll by Perkin and Duppa 21 so that Kolbe was able 

 to write : 



,(C 4 H 5 )C,(X,O HO, 

 Propionic acid. Alanine. 



Lactic acid. 



](5 Annalen. 75, 27. 17 Comptes Rendus. 45, 306. 18 Ibid. 46, 

 1228. 1!) Annalen. 109, 257. 20 Ibid. 91, 185. 21 Ibid. io8, 106. 



R 



