LECTURE XIII.] HISTORY OF CHEMISTRY. 259 



In this discussion, so far as we have considered it as yet 

 (up to 1859), Kolbe's way of regarding the matter was better 

 adapted to explain the facts than that of Wurtz. In particular, 

 it was possible to explain, in a very satisfactory manner, the 

 relations between the fatty acids and the lactic acids, as well 

 as the phenomena of isomerism amongst the ethers of the 

 latter acids, which Wurtz discovered in the following year. 31 

 What Kolbe misunderstands, are the relations, pointed out by 

 Wurtz, between the glycols and these acids; 3 ' 2 and even in 

 1860, when he returns to the constitution of lactic acid, he still 

 adopts the same standpoint. 33 He emphasises the difference 

 between the two hydrogen atoms, replaceable by radicals, in 

 lactic and glycollic acids; but he does not admit that the 

 hydrogen peroxide groups which they contain, also occur in 

 the glycols. 



Wurtz, meanwhile, has gone a step further. He introduces 

 a distinction between atomicity and basicity in the case of 

 acids. 34 Whilst the former of these is determined by the 

 valency of the radical present, the latter is regulated by the 

 number of hydrogen atoms replaceable by metals. According 

 to Wurtz, "the capacity of saturation of an acid towards basic 

 oxides depends not only upon the number of equivalents of 

 typical hydrogen which it contains, but also upon the electro- 

 negative nature of the oxygenated radical. In proportion as 

 the oxygen increases in this radical, the typical hydrogen 

 becomes more and more basic hydrogen." 



This is illustrated by the following example : 



CTT "v (~~* TT (~\\ f~* (~\ ~\ f~* T. 



oil, \ r^ L/orloU I /% ^oUfttjm ^9* 



Glyceric acid is triatomic but only monobasic ; phosphorous 

 and cyanuric acids are triatomic and dibasic. Further, Wurtz 



31 Ann. Chim. [3] 59, 161. :52 Compare especially Annalen. 109, 262 etc. 

 33 Ibid. 113, 306. 34 Bull, Soc. Chim, I, 33; Ann. Chim. [3] 56, 342, 



