122 MR. E. SCHUNCK ON THE ACTION OF 



process of extraction by the action of the ferment on the sugar 

 contained in the extract. 



A few years ago the only known sources of succinic acid 

 were amber, turpentine, and some species of brown coal and 

 retinasphalt. Latterly it has been discovered in several 

 plants, such as the Lactuca sativa and virosa* and the 

 Artemisia Absmthium,'\ and it has been detected in the liquid 

 extracted from cysts containing echinococci from the human 

 liver.J It has moreover been produced artificially by the 

 action of nitric acid on different kinds of fat and fatty acids, 

 such as tallow, wax, spermaceti, and stearic and margaric 

 acids, II and its formation during the fermentation of aspara- 

 gine, malic acid and their compounds is one of the most 

 interesting facts of organic chemistry. As far as I know, 

 however, its direct formation from sugar has not hitherto been 

 observed, and I consider this as the most important fact 

 revealed by this investigation. In future, should its presence 

 be detected in any part of the vegetable or animal organism, 

 its origin need no longer be a subject for doubtful speculation, 

 as it is now known to be a product of the decomposition of 

 sugar, whether it be cane sugar, grape sugar, or sugar of 

 milk.§ 



* Kohnke, Brandes Arcbiv, 2 ser., XXXIX. 153. 



t Zwenger, Annalen der Pharmacie, XLVIII. 122. 



J Heintz, Poggendorff's Annalen, LXXX. 114. 



II Bromeis, Slhamer, Radcliffe, Ronalds, Annalen der Pharmacia, XXXV. 

 90; XLIII. 340, 349, 356. 



§ The only indication which I can find of the formation of succinic acid 

 from sugar having previously been observed, is a statement of Beissenhirtz 

 (Berlinisches Jahrbuch der Pharmacie, anno 1818, p. 158), who allowed a mix- 

 ture of honey, bread, siliqua dulcis (the fruit of the ceratonia siliqua), vinegar, 

 spirits of wine, and water, to ferment, neutralized the acid with lime, and then 

 subjected the solution of the lime salt to distillation, together with oxide of 

 manganese and sulphuric acid, when he obtained first a distillate of acetic acid, 

 and afterwards a sublimate of succinic acid. Here the siliqua dulcis probably 

 yielded only the ferment, since John could discover in it no succinic acid, ready 

 formed, and the honey the sugar acted on. Pliimacher repeated this experi- 

 ment, but without success. Piria discovered that asparagine is formed during 

 the germination of the seeds of various leguminosse, such as peas, beans, and 



