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stituent parts of milk. SCHEELE now discovered 

 the saccholactic acid and the lactic acid, and de-< 

 moiistrated several chemical properties of the 

 milk. A considerable time afterwards, milk 

 and lactic acid were examined by BOUILLON- 

 LAGRANGE and by THENABD, who declared 

 the acid to be the acetic, united with a peculiar 

 animal matter, from which it could not be sepa- 

 rated by distillation. FOXTRCROY and VAUQUE- 

 LIN gave us after this an ample analysis of milk, 

 in which they still further rejected SCHEELE'S 

 lactic acid, because its salts, when distilled with 

 sulphuric acid, produced an empyreumatic acetic 

 acid ; but as this is the case with several other 

 fixed vegetable acids, which still are not con- 

 sidered as acetic acid, the arguments of the 

 French Chemists seemed not satisfactory. 1 

 have* myself, also endeavoured to ascertain the 

 composition of this substance, and have obtained 

 results, which had escaped the attention of my 

 predecessors. I have proved that, in the forma- 

 tion of butter, air is absorbed, and not disen- 

 gaged, as some Chemists assert, this disengage- 

 ment only taking place, when the milk is in & 

 fermenting state, and has become impregnated 

 with carbonic acid gas. I have further proved, 

 that cheese occurs dissolved in the milk in a 



