General Refults concerning Sugar, Mucilage, i^fc, 4,1 1 



ftate, or if it was pofTible to convert it into an acid, by mere expofure to the air, without 

 the addition of fome fubftance containing much oxygen, as the nitrous or oxygenated muriatic 

 acids. Accordingly a folution of gum arabic, mixed with a proper proportion of good yeaft, 

 was introduced into an open vefle), and kept at a temperature ranging from 68° to 75° for 

 twenty-fix days, but during this period nothing like fermentation was perceived : the 

 mixture at laft emitted a very peculiar and ofFenfive fmelj : the gum, however, ftill retained 

 its natural tafte, and was not in the le*(l four. In this cafe it fliould appear, that the 

 azote, and lime, which in the gum are combined with carbon, hydrogen, and oxygen, 

 prevented the vinous fermentation, and confequently the formation of any thing like vinegar. 



It has been fuppofed, that a deco£lion of purely animal matter might undergo certain 

 fpontaneous changes, and at laft become acid. In order to determine this point, about 

 fixteen ounces of a ftrong decoftion of beef were introduced into an open veflel, and kept 

 at the temperature of about 68° or 70°. A few days after, an equal quantity of a fimilar 

 decodlion, mixed with an ounce of yeaft, was likewife expofed in an open veflel to air of 

 the fame temperature. 



At the end of five days, the deco£lion,' without any mixture, began to fliew evident 

 marks of putrefadlioj^, but did not in the Icaft tafte acid, nor had it ever fliewn any figns 

 of vinous fermentation j in two days more it became extremely oiFenfive, accompanied 

 with the produ£lion of ammonia. 



The decoQion with the yeaft did not fhew any evident figns of putrefaSion until the 

 feventh day, but there was nothing like fermentation perceived ; in two days more it 

 became extremely putrid and offenfive, and was thrown away. 



Hence it fliould appear, that neither vegetable nor animal mucilages are, when pure, in 

 any degree fufceptible of the vinous fermentation : indeed, thefe are fa£l:s which have been 

 fo generally admitted, that, had not a contrary opinion been lately advanced, we flaould 

 have conceived the three laft experiments unneceflary. 



The miftake has no doubt arifen from obferving the facility with which a decoftion of 

 a mixture of animal and vegetable matter runs into the acid ftale : but in this cafe the 

 animal fubftance performs the part of yeaft only ; and it is in this way that diabetic urine fo 

 readily ferments fpontaneoufly, and becomes vinegar. 



From the preceding experiments we may draw the following conclufions : 



ift. That fugar confifts of carbon, hydrogen, and oxygen ; and may be confidered 

 as a pure vegetable oxyde. 



ad. That fugar of milk is compofed of the fame principles, but contains more oxygen 

 and confiderably kfs charcoal. 



3d. That gum differs from fugar in containing, befides carbon, hydrogen, and 

 oxygen, both lime and azote. 



4th. That vegetable farina cannot be converted into faccharine matter, without the joint 

 aftion of oxygen and water ; the firft of which appears to be abforbed, and the lait 

 decompofed, during this procefs. 



5th. That when fugar is deprived of its oxygen, or combined with other fubftances> 

 it lofes its charafleriftic properties, and is no longer fufceptible of the vinous fermentation. 



6th. That neither vegetable nor animal mucilages, in their pure ftate, are fufceptible of 

 this procefs. 



VIL Or* 



