LACTIC ACID. 261 



7. The cheefy matter, when feparated, always manifefls 

 the prefence of an acid, and differs in tafte and confidence 

 according to the matters employed in its feparation. 



8. When warned and affording no fign of acidity, if it be 

 efterwards difnifed in diftilled water for feveral days, at a 

 temperature between 15 and 22 degrees (about 65 and 80 

 Fahrenheit), it acquires a ftrong difagreeable odour ; the fluid 

 {lightly reddens turnfole, and lime difengages ammonia. 



9. The ferum and the cheefy matter contain, beiides the 

 known fubflances, phofphate of lime, as Scheele had an- 

 nounced. 



10. The difference which exifts between frefh ferum and 

 that which has been expofed to the air, confifts in the acetic 

 acid, which is prefent along with the free acid in the milk. 



ll.Laftly, there exifts in milk and the ferum a free or 

 ancombined acid, which feemed to me to be the acetic acid, 



SECTION V. 

 Concerning the Lactic Acid. 

 Scheele having afcertained that it is not poffible to obtain Laflic acid, not 

 the acid by Ample diftillation, had recourfe to peculiar me- £ a '," e JiftHi t . 

 thod's to efFedt this feparation. tion. 



This chemift faff, reduced the whey to one-eighth by eva- Scheele's pro- 

 portion ; he then filtered it, and there remained, according ^ {s ' tewhe 

 to him, no more cheefy matter. to one-eighth. 



Hefaturated the fluid with lime-water, and phofphate f Fiker - Saturate 

 v • ■ , _. .. ,. ,-,/.,, , with lime-wafer, 



Jime was precipitated : This liquor having been filtrated and w h; c h throws 



diluted with three times its quantity of water, he poured in down phofphate." 



i- -ii i i /- • i • . nil- Filter. Dilute 



oxalic acid drop by drop, to (eize and precipilafe all the lime; with water> Pie . 



and he afcertained, by the addition of a little lime-water, cipitate lime by 



that no more oxalic acid remained. He evaporated the liquor Jorate tomualus 



to the confiffence of honey ; the thickened acid was re- confiftence. Dif- 



diflblved in redified alcohol; the fugar of milk and all the f ? lv f, ^ fjf in 



. ° alcohol and filter. 



t-oreign fubftances remained on the fibre, not having been Then add water, 

 diflblved by the alcohol. Lafr.lv, after having again added a and diftil offthe 

 r.,i .... -i . i. • r, • ,,,,,, alcohol. Refidue 



httle water to the acid held in folutton by the alcohol, he ls bale acid. 



drew off" this laft fluid by diftillation, and found the la&ic acid 

 in the retort. 



This long and expenfive procefs does not afford a pure It is not pure, 

 acid. It was therefore necedary to adopt a Ampler procefs 

 before its nature was examined. 



Experiment 



