CHEMICAL PHYSIOLOGY. 103 



stage between bilirubin and urobilin ; on hsematoporphyrin, 

 by A. E. Garrod (Jour. Physiol., xv. 108), who considers 

 this substance to be a constituent of normal urine which 

 is much increased in a variety of pathological conditions ; 

 and by L. Zoja (Cent. Med. Wiss., 1892, 705), who 

 compares together the properties spectroscopic and other- 

 wise of hsematoporphyrin and uroerythrin. He regards 

 MacMunn's urohsematoporphyrin as a mixture of hsemato- 

 porphyrin with urobilin. On uric acid, by G. Salomon (Yir- 

 chow's Archiv, cxxxii. 170). In relation to Horbaczewski's 

 work, the author advances a claim for priority. C. Wulff 

 (Zeit. pkysiol. Chem., xvii. 634) criticises Horbaczewski's 

 work on the formation of uric acid from nuclein, which, 

 however, that observer has since defended (see para- 

 graph on Proteids). On Phenol in urine a paper by 

 Kossler and Penny (ibid., xvii. 117) gives an excellent 

 account of the methods of estimating- this substance 

 volumetrically. 



A number of papers on sugar in urine will be found 

 referred to in the paragraph on Carbohydrates. In addi- 

 tion to these the student of diabetes should consult the 

 following : the Relation of the Urinary Carbohydrates to 

 Humous Substance, E. Salkowski (ibid., xvii. 229) ; on 

 /3-hydroxybutyric acid in the organism by T. Araki (ibid., 

 xviii. 1); here support is lent to Minkowski's theory that 

 acetone and aceto-acetic acid originate from this substance. 

 There are also a number of papers on artificial diabetes, 

 namely, on Pancreatic diabetes (V. Harley, Brit. Med. 

 Jour., 1892, ii. 451); and on Phloridzin diabetes by 

 Cremer and Ritter (Zeit. Biol., xxvii. 459, xxix. 256), 

 by W. Prausnitz (ibid., xxix. 168), and by M. Cremer 

 (ibid., xxix. 157). These' work out various points of 

 detail in connection with this subject but do not add 

 anything striking to our knowledge of the diabetic 

 condition. 



One other abnormal condition of the urine remains to 

 be mentioned, and here H. Embden (Zeit. pkysiol. Ckem., 

 xvii. 182) fully confirms Baumann and Wolkow's con 



