352 MESSES. E. FBANKLAND AKD B. F. DUPPA'S 



/CH3 _|_pQi fCHa .^poa,, 



ICHO ' ICHCI2 * 



.Aldehyde. Ethylidene 



dichloride. 



the oxygen in the aldehyde being simply replaced by chlorine. There now only remains 

 one possible formula for ethylene, viz. 



or 



CH2 



Ic 



Such, then, being the constitution of ethylidene and ethylene, it follows that the former 

 ought to give rise to an acid of the constitution shown in formula No. 1, whilst ethylene 

 should produce an acid agreeing with formula No. 2. The acids actually produced from 

 these sources are lactic and paralactic acids ; hence we believe No. 1 to be the constitu- 

 tional formula of lactic acid, and No. 2 that of paralactic acid, a conclusion which har- 

 monizes perfectly with all the reactions in which the production of these acids can be 

 traced. Thus in the formation of lactic acid by the oxidation of propylic glycol *, we 



^^"'^ ;C Me H Ho , ^ f C Me H Ho J „ ^ 



icH,Ho +^^=lcOHo +^^^- 



Propylic glycol. Lactic acid. 



Again, the production of this acid from ethylidene cyanhydrate, 



JCH3 +KHO+H2 0=1^53^^ _^_ ,+NH3. 



iCHHoCy ' LCHHo(COKo) 



Ethylidene Potassic lactate, 



cyanhydrate. 



The formula given for potassic lactate in this equation is only apparently different in 

 type from that previously used for lactic acid, since 



CH, r... TTTT /^^T^ N (CMeHHo 



|CH3 =CMeHHo(COKo)=|^^ 



lCHHo(COKo ^ ^ (CO 



lCHHo(COKo) ' ' (COKo 



In Uleich's f interesting reaction, by which chloropropionic acid is transformed into 

 lactic acid, we have the following change : 



(COHo tCOKo ' 



Chloropropionic Potassic lactate, 



acid. 



The production of lactamic acid (alanin), and that of lactic acid fr-om the latter by 

 the action of nitrous acid, are also clearly confirmatory of the above view. 



* WuEiz, Ann. der Chem. und Phana. Bd. cv. S. 205. t Ann. der Chem. und Pharm. Bd. cix. S. 271. 



