336 DR A. CRUM BROWN ON THE CLASSIFICATION OF 



Derived from the aldehydes and acetones, we have another series of substances, 

 having well-marked reactions in common, and forming what we may call a 

 subgenus of the genus containing the radical H. These are the acids obtained 

 by the action of HC1 and HCN, on the aldehydes and acetones. The mode of 

 formation of these acids appears to be the following : — To the aldehyde or ketone 

 HCN is first added in the same way as H 2 is added to form the alcohol, a body 

 which may be called an oxynitrile being then produced. 



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(this stage of the reaction can be traced in the case of bitter almond-oil ; the so- 

 called hydrocyanate of bitter almond-oil being, no doubt, the nitrile of mandelic 

 acid). In the second stage of the reaction this nitrile is decomposed (like other 



nitriles) by the HC1 and water, yielding NH 4 C1, and the acid ©-©-©-© 



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by this reaction it will be seen that the radical (CO)" has been transformed into 

 (C(HO)H)" or ($H)", which is therefore the generic radical of this series of acids. 

 This genus may (like the acetones) be subdivided still further, the aldehydes 

 giving rise to acids containing ($HE)' (or 0H), the acetoketones to those containing 

 (0CH3S)', &c. The best known of these subdivisions is that containing (05)'. 

 As indicated by the generic radical, these bodies have the properties both of acids 

 and alcohols, giving rise to salts by the replacement of the hydrogen in the 5 by 

 metals, and to ethers by the replacement of the (HO) in the by salt radicals 

 (acids minus H). Some of them, at least, seem capable of forming aldehydes ; for, 

 as Debus has pointed out, glyoxylic acid is the aldehyde of glycollic acid. (It is 

 worthy of note, that glycollic acid is the only member of the series which is a 

 " true" alcohol, containing the radical (H0)', and giving rise, by oxidation, to an 

 aldehyde and an acid — glyoxylic and oxalic acids). The typical formulas of Fkank- 

 land and Duppa indicate in a different way the same constitution as that 



[OP 



HO 



expressed by the radical formulae above ; C 2 , ttt) being obviously identical with 



R 2 



