300 ISIDOR GREENWALD 



"isoglycuronic acid" cannot be allowed. In one paper (1915) the melting 

 points of four different preparations of the p-bromphenylosazone of the 

 substance from urine are given as 196, 197, 197 and 198. In another 

 paper (1916) it is given as 236, and that of "true levulose" as 197 and 

 of dextrose as 220. But the fact is that the p-bromphenylosazone of 

 glucose is identical with that of fructose and melts at 222. On having his 

 attention called to this, Cammidge (cT) replied that this was due to an error. 

 Substituting the values given in his letter this sentence would read, "The 

 (p-bromphenyl) osazone of pseudolevulose melts at 197, that of true levu- 

 lose at 220, and the osazone of dextrose at 220, while the hydrazone of 

 glycuronic acid melts at 236," which certainly does not indicate that 

 Gammidge realized that the compounds obtained from "levulose" and 

 "dextrose" were identical. The melting point of the unsubstituted phenyl- 

 osazone of the "pseudolevulose" is given as 223, "7 lower than the 

 melting point of dextrosazone and levulosazone." But the melting point 

 of this compound is generally accepted at 204-205. In his letter, Cam- 

 midge ascribes the difference to his use of the Maquenne block instead of a 

 capillary tube for the determination. For the value of 230 for the melt- 

 ing point of phenylglucosazone, Cammidge has the high authority of Ber- 

 trand. But Miither and Tollens found that the melting point of glucosa- 

 zone to be practically the same by either method, with somewhat greater 

 variability when using the block. Certainly, it is strange that Cammidge 

 and Howard should observe a difference of 25 with one compound and 

 none, or very little, with two others (the p-bromphenylhydrazin compound 

 of glycuronic acid and the p-bromphenylosazone of fructose or glucose). 

 Cammidge and Howard identify their "isoglycuronic acid" by oxidation 

 to arabonic acid with lead peroxid and sulphuric acid, a reaction not 

 described elsewhere in the literature as employed for any closely related 

 purpose, and then prepare the barium salt by boiling with barium car- 

 bonate. This salt is then decomposed by passing carbon dioxid into an 

 aqueous suspension and boiling. Why the reaction should so easily reverse 

 itself is not explained. No substance having the properties ascribed to 

 "isoglycuronic acid" by Cammidge has been described by others. It would 

 seem that work involving such new chemical reactions and observations 

 should not be casually published in a medical journal, as if well-known and 

 established, but should be fully described in a chemical publication where 

 it would come directly to the attention of chemists. 



Fructose Tolerance. Test for Hepatic Function. In 1901 Strauss 

 (&) described a fructose-tolerance test for hepatic function. He found that 

 patients with evidence of hepatic disorders, other than passive congestion, 

 excreted at least a small part (1 or 2 gin.) of 100 gms. of fructose taken 

 on a fasting stomach. Of patients with other conditions, only 6 out of 58 

 gave positive reactions. With the exception of Landsberg, most other 

 workers have confirmed the diminished tolerancy in marked hepatic dis- 



