258 Prof. Latham, On the formation of lactic acid, [May 11, 



May 11, 1885. 

 Prof. Foster, President, in the Chair. 



The following communications were made to the Society:— 



(1) On the formation of lactic acid, creatine and urea in 

 muscular tissue. By Prof. Latham, M.D. 



The variety of lactic acid which is obtained by the disintegra- 

 tion of albuminous compounds and is formed during the contraction 

 or tetanus of muscular fibres, and hence called sarco-lactic acid, 

 though agreeing in some respects with fermentation or ethidene 

 lactic acid, differs from it in being optically active, turning the 

 plane of polarization to the left, whereas the other is optically 

 inactive. The difference too between their calcium and zinc salts 

 is very marked. In rheumatic fever, again, it is formed in large 

 quantities in the system, and differing as above stated, from fer- 

 mentation lactic acid, the inference is obvious that it cannot be 

 directly formed from the glycogen in the tissues, or from saccharine 

 or starchy matters introduced into the digestive tract. In fact, in 

 the disorder referred to, one of the most important aids in cutting 

 short the malady, and putting a stop to the excessive formation of 

 lactic acid, is to place the patient entirely on a diet of farinaceous 

 food and milk. 



Where then does it come from ? The question possesses much 

 more than a physiological interest, for if rightly answered a con- 

 siderable insight will be gained into the pathology of the disorder 

 to which I have referred. 



Sarco-lactic acid may be regarded as a mixture of two kinds of 

 lactic acid* the more abundant being paralactic acid or ethi- 



{OTT 

 / ^ l/ ~. / -. T - r , the other ethene lactic acid 

 COOH 



CEL . CH i^^^-r-r . Now these two acids may be obtained, 

 2 2 (COOH J 



(i) by oxidising ethylic alcohol, treating the aldehyde so ob- 

 tained with hydrocyanic acid to form a cyanhydrin, and acting 

 upon this with acids or alkalis — 



2 H 5 . HO + = CH 3 . CHO + H 2 

 ethyl alcohol aldehyde 



CH 3 . CHO + CNH = CH 3 . CH |^ 



aldehyde cyanhydrin 



CH 3 . CH [^ + 2H 2 = NH 3 + CH 3 . CH ^ QR f 



ethidene lactic acid 



* Watts, Dictionary of Chemistry, Vol. vni. p. 1160. 

 + Fownes, Manual of Chemistry, 1877, p. 625. 



