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XXXVTI. An Investigation of the Properties of Lactid 

 ^cid. By Jacob Berzklius, Professor of Medicine and 

 Pliarmncy, and M.R.J. Stockholm. Translated from 

 the SivediA*. 



A. HE lactic acid was discovered by Scheele. He allowed 

 sour milk to coagulate, filtered the fluid, and boiled it away 

 to 1 8tl) ; he then filtered it again, to separate the curd 

 which was deposited. This acid fluid he saturated with 

 liiTie water, which threw down a precipitate ot bone' earth ; 

 the remaining; lime was cautiously separated by the addition 

 ot' oxalic acid, taking care that it should not be in excess, 

 and the fluid was evaporated to dryness. The acid was 

 then dissolved in alcohol, which, after evaporation, afforded 

 it in the purest state that was then known. Scheele deter- 

 mined the relations of this acid to the greatest number of 

 bases so clearly and accurately, that there was no reason to 

 entertain any doubt of its proper nature, as essentially di" 

 'stinct from all other acids. The assertions of Scheele have 

 however within the last few years not only been called in 

 question, but even positively contradicted, by some French 

 chemists, Bouillon Lagrange, Thenard, Fourcroy, and Vau- 

 quelin. Snice only the two last chemists have had suflfi- 

 cient confidence in their scientific character to decide posi- 

 tively on this question, in contradiction to the results of 

 Scheeli's txperimeuts, I shall here only say a few words 

 rtspectiog their assertions. Among the properties of the 

 lactic acid, Scheele lias mentioned that it is not volatile, and 

 that it is destroyed by distillation, and affords a sour spirit; 

 a name, by which the empyreumatic vinegar, which is ob- 

 tained in the distillation of organic substances, was thea' 

 aii^ays distinguished, in their investigations respecting 

 this acid, the French chemists saturated it with an alkaii, 

 mixed the salt with concentrated sulphuric acid, and di- 

 stilled the mixture. The liquid distilled contained a weak 

 vinegar, which was saturated with alkali, was evaporated 

 to dryness, and Was distilled ag:iin with sulphuric acid. It 

 requires no great depth of cliemical knowledge to discover 

 the improprTety of tliis mode of operation, and the neces- 

 sity of the formation of vinegar at the expense of the com- 

 ponent parts of the lactic acid destroyed. On the otheP 

 hand, these chemists seem not to have paid the slightest 

 allemion to the proper characteristic salts, which are pro- 

 duced by the lactic acid with diflcrent Irases, and from 



• From the Animal Chemistry of Profejwr BerzeliiM.vol. ii. p. 430. 



Vol. 41. No. ISO. y^pnM8l3. Q which 



