1875.1 ^1' [Sadtler. 



In favor moreover of the normal structure for the molecule of glyceric 

 acid is the formation of pyruvic or pyroracemic acid 



CHo 

 CO 



CO. OH 

 from glyceric acid upon heating this to 140°, explained by the following 

 reaction : CH^-OH CHg 



CH.OH — H.OH = bo 

 CO. OH CO. OH. 



The structure of this pyruvic acid is known from the fact that acted 

 upon by nascent hydrogen it gives normal lactic acid. 



A strong additional argument would be had, if we could show a con- 

 nection between glyceric acid, CHj.OH 



CH.OH 



CO.OH 



and tartronic acid, CO.OH 



CH.OH 

 CO.OH. 

 Hitherto tartronic acid had not been formed from glyceric acid, but 

 only in an indirect way, by the spontaneous decomposition of nitro- 

 tartaric acid, according to the following reaction : 

 CO.OH CO.OH 



CH.O(?^0,,) CH.OH 

 CH.OCNO,,) = CO.OH + -^^Os + CO2 

 io.OH 

 However this mode of formation was interesting as tending to show its 

 symmetry of structure. For that matter a dibasic, triatomic acid could 

 hardly exist, exceist by the assumption of two carboxyl groups. 



I have been fortunate enough to find tartronic acid associated with gly- 

 ceric acid in the oxydation products of glycerine. The preparation of 

 the two acids was as follows : One part by weight of glycerine is 

 mixed with one part of water, and to the mixture is added, by means 

 of a long funnel tube reaching to the bottom of the cylinder, about 

 one and a quarter parts of red fuming nitric acid. After allowing 

 them to rest until all gas evolution has ceased, (which usually takes some 

 six days,) the solution is evaporated down at a gentle heat until the 

 fumes of nitric acid are no longer perceptible. It is then very thick 

 and syrupy. It is now diluted with water, and plumbic carbonate is 

 added in excess. The oxalate and undissolved carbonate are filtered off, 

 and the solution slightly concentrated and allowed to crystallize. The 

 glycerate of lead deposits in thick crystalline crusts. These are separated 

 from the mother-iiquor, dissolved, and the lead precipitated out from the 

 solution by sulphuretted hydrogen. 



