SYNTHETICAL RESEARCHES ON ACIDS OF THE LACTIC SERIES. 



349 



8th. Btheric Secondary Olefine Acids. — These acids are related to the secondary 

 define acids in the same way as the sixth division to the fifth. No member of the 

 seventh or eighth division has yet been formed. 



Isomerism in the Lactic Series. 

 The members of the lactic series may be defined as acids containing one atom of 

 oxatyl, the fourth bond of the carbon of which is united with the carbon of a basylous 

 group containing one atom, and one only, of hydroxyl, or of the peroxide of a radical, 

 either alcoholic or acid. The following examples, expressed in the graphic notation of 

 Crum Beown *, will serve to illustrate this definition. 



Acids of the Lactic Series. 



Lactic acid. 



Methyl-lactic acid. 



Aceto-Iactic acid. 



The synthetical study of the acids of this series affords an insight into numerous and 

 interesting cases of isomerism, which have hitherto received, at best, but a very imperfect 

 explanation. Commencing with the lowest member of the series, we have for glycoUic acid 



* Edinburgh Phil. Trans, for 1864, p. 707. It is much to be desired that chemists should employ these 

 graphic formulse in all cases where they wish to express the mode in which they suppose the elements of a 

 chemical compound to be combined. It is often extremely difficult to trace in symbolic formulae, the exact 

 meaning which the author attaches to the grouping of letters ; in graphic formulae no such difficulty can arise ; 



MDCCCLXVI. 3 B 



