1875.] t)iJ [Sadtler. 



.4348 grms. salt yielded .1323 grms. H^O equal to 3.38 per cent, 

 hydrogen. 



The theoretical per cent, of hydrogen in C:5H^05 is 3.33. 



An important test that I wished to make but was compelled to forego 

 for the time, was to act upon this tartronic acid with hydrogen iodide. 

 Were its structure symmetrical, it should yield « iodo-malonic acid, 

 which by further treatment with HI or with reducing agents would yield 

 malonic acid. 



Wishing to obtain larger quantities of the tartronic acid for further 

 examination, I have since oxydized another portion of glycerine and 

 treated the products in the same way. This time I got no tartronic acid 

 whatever, at least only a trace of calcium salt remained undissolved on 

 heating with water. Evidently here the oxydation had proceeded some- 

 what differently as no tartronic acid formed. This result is not sur- 

 prising on reflection, as the oxydation by nitric acid is not capable of 

 much control, and a product once formed is liable to be still further 

 oxydized. Thus glyceric and tartronic acids are both liable to be 

 oxydized into oxalic acid, which always forms in considerable though 

 varying quantity. Indeed the oxydation of glycerine by nitric acid is 

 now known to yield a variety of products, of which, however, no doubt 

 some ai'e secondary ones. 



Thus Heintz* has proved that racemic, formic, glycolic, and glyoxalic 

 acids are all found associated with the glyceric and oxalic acids in this 

 product. 



The tartronic acid just found, therefore, is only one of several smaller 

 side-products. The known symmetry of structure of the molecules of all 

 these side products, however, certainly argues in favor of a similar sym- 

 metry in the glyceric acid molecule. 



There is one way of reconciling these two views of the structure of 

 glyceric acid, and that is the assumption of the existence of two isomei'ic 

 acids, of which one is normal and the other an unsymmetrical acid. 



Some results that I have just obtained in ijurifying the calcium gly- 

 cerate seem, indeed, to point this way. Should the unsymmetrical gly- 

 ceric acid pi'eponderate in this mixture, Wislicenus' reactions with hydro- 

 gen iodide are readily understood. Another fact, which should not be 

 lost sight of, is that in the decomposition of /5 iodo-propionic acid by 

 moist silver oxide, Wislicenusf obtained not hydracrylic acid alone, but 

 three other products accompaning it, so that the decomposition was not 

 so simple. 



I am now engaged upon a study of this question and hope to be able to 

 give more information upon it, in a short time. 



* Ann. der Oh. und Ph. 152, p. 325. 



t Ann. der Oh. und Ph. 168, p, 41. 



A. F. S. — VOL. XIV. 4b 



