354 



MESSES. E. ITIANKLAND AJ^D B, F. DUPPA'S 



lactic acid, it follows that the former chloro-acid must be isomeric, and not identical, 

 with the latter. Now, although the formula of propionic acid does not admit of any 

 isomer, yet that of chloropropionic acid does, as is seen in the following graphic formulae. 



No. 2. 



No. 1. 



A comparison of these formulae with those of lactic and paralactic acids (page 351) 

 shows at a glance that No. 1 is the chloropropionic acid which yields lactic acid, whilst 

 No. 2 is iso-chloropropionic acid, which, by the substitution of its chlorine by hydroxyl, 

 must yield paralactic acid. By the action of nascent hydrogen, both isomeric chlorides 

 will obviously produce the same propionic acid. 



The cause of the isomerism of methyl-glycoUic acid (No. 3, page 351) is so obvious as 

 to require no further explanation. Proceeding to the next higher stage in the series, 

 such is the rapid increase of isomerism, that we now encounter no less than eight pos- 

 sible isomers, all within the lactic family. 



Normal. 

 No. 1. 



Ho 

 Ho * 



fCEtH 

 ICOHc 



Secondary. 

 No. 2. 



f C Meg Ho 

 IcOHo ■ 



Etheric normal. 

 A 



No. 3. 

 ,Eto 



No. 4. 



rCHgEto rCMeH 



ICOHo ■ IcOHo 



Meo 



Normal define. 



A 



No. 5. 



CHgHo 

 C H2 

 CH2 

 ^COHo 



No. 6. 

 rCHgHo 

 CMeH. 

 COHo 



No. 7. 

 rCMeHHo 



CH2 

 COHo 



Etheric normal olefine. 



No. 8. 



rCHgMeo 



CH2 

 COHo 



Of these acids, Nos. 1, 2, and 3 are known. No. 1 is oxybutyric acid; No. 2 is di- 

 methoxalic acid, which is probably identical with Staedeler's acetonic acid*. On this 

 assumption, the formation of the latter by the action of hydrocyanic and hydrochloric 

 acids upon acetone is easily intelligible. 



/CH3 ^CN"'H+2H2 0+HC1 = |^^^2^^+N^H4C1. 



[CO Me 



Acetone. 



Acetonic or 

 dimethoxalic acid. 



* Ann. der Chem. uad Pharm. Bd. cxi. S. 320. 



