2^4 ANALYSIS OF ONIONS. 



to en ted onion juice, this substance contains a small quan- 

 tity of fermentable sugar, which was observed by Proust 

 and Thenard ; also a small portion of yellow matter of a 

 nauseous smell and taste, which fermentation does not de- 

 stroy, and to which they think its purgative quality is to be 

 ascribed; and lastly a little mucilage, which alone is con- 

 verted into mucous acid when manna is treated with nitric 

 and. Melon-juice in like manner affords tiiem manna, 

 which they could riot discover previous to fermentation. 

 Spirituous fcr. Desirous of knowing whether onion-juice, as a saccharine 

 onion juice. liquor, be capable of affording alcohol on the addition of a 

 suitable ferment, our authors mixed 244 gr. [37^7 gi's.] of 

 this juice, reduced to the consistence of an extract, with 

 2 lit. [2 wine quarts] of water, and 30 gr. [4G0 grs] of beer 

 yeast of the consistence of paste. The mixture, exposed to 

 a temperature of r6° or 20° [6l° to 68° F.], exhibited all 

 ihe phenomena observed during alcoholic fermentation. Car- 

 bonic acid was evolved ; and the distillation of the ferment- 

 ed liquor yielded 134 gr. [20G[) grs] of brandy at 2-2°, equi- 

 valent to 73 gr. [11 27 grs] of alcohol at 40°. This quantity 

 of alcohol, according to Lavoisier, requires for its produc- 

 tion 1 14 gr. [1760 grs] of sugar. 



(> neral results From the experiments above related it follows, that the 



of -lie analysis . T ,, . . . . , _ ■ , 



of the onion, onion is composed or, 1, a white, acrid, volatile, and odorous 



oil : 2, sulphur combined with oil, which occasions its fetid 

 smell : 3, a large quantity of uncrystallizable sugar : 4, a 

 great deal of mucilage analogous to gum arabic : 5, a 

 vegetq-animal matter coagulable by heat and analogous to 

 gluten ; 6, phosphoric acid, partly free, partly combined 

 with lime; and acetic neid ; ; 7, a small quantity of citrate of 

 lime, which had never before been met with in vegetables: 

 8, a parenchymatous or very tender fibrous substance re- 

 taining ' e<reto-auimal matter. 

 Sources of its It is to the combination of the oil of the onion, the sul- 

 uropcrties. phur, the saccharine substance, and the mucilage, that we 

 must ascribe the emulsion or milk, that flows from the 

 slices of this bulbous root, its acrimony, its property of.irri- 

 Acrimony of tatirig the eyes, exciting tears, blackening silver, &c. Most 



plants resides acr j ( i plants, as the .euphorbias, chelidouias, arums, h-lle- 

 inan oil, or re- ..... .% : '.. , , 



sin, and best bores, owe then- injurious quaities to oily and resinous sub- 

 stances : 



