428 THE CHEMISTRY OF TUMORS 



plasma cells (Wright) or from the neutrophile myelocytes or 

 their predecessors (Muir). 



Properties of the " Bence-Jones Proteid." Not to go 

 into details, which are given in the literature cited, the impor- 

 tant facts concerning the "Bence-Jones proteid" and its appear- 

 ance in the urine (" myelopathic albumosuria," Bradshaw), are as 

 follows : 



It is a proteid, the exact nature of which has not been deter- 

 mined ; at first considered an albumose because of its peculiar 

 reactions to heat, its nature has since been contested, but the 

 weight of evidence seems to be in favor of the contention of 

 Simon that it is most closely related to the water-soluble globu- 

 lin of 'the blood. Its most characteristic properties are the fol- 

 lowing : 



The coagulation temperature is low, varying from 49-60 in various 

 cases, and being considerably modified by the amount of salts and urea 

 present in the solution. 



In many cases the coagulum is redissolved on heating, and reappears 

 on cooling, but this characteristic feature is not always present, and 

 often disappears in cases where at first it is present. 



A precipitate is formed by strong (25 per cent. ) nitric acid, which dis- 

 appears on heating and reappears on cooling. Strong hydrochloric acid 

 causes a dense precipitate, which is quite typical (Bradshaw). 



No precipitate is produced by acetic acid, even in excess, and the 

 addition of acetic acid to a hot coagulated specimen causes prompt solu- 

 tion of the coagulum. 



Unlike albumoses, this substance does not dialyze ; the salt-free solu- 

 tion left in the dialyzing bag does not precipitate. 



A purplish-violet color is usually given with the biuret reaction, but 

 it may be more reddish in color, especially if little copper is present. 



Sulphur is readily split off by alkalies, reacting with lead acetate to 

 produce lead sulphide (Boston). 



After standing in alcohol, by which the body is precipitated, it loses 

 its solubility (differing in this respect from albumose). 



As to the exact nature of the body, little can be said at 

 the present time. Since protoproteoses, deuteroproteoses, and 

 peptone are split off on digestion with pepsin, the molecule is 

 evidently larger than that of any of the albumoses. The well- 

 purified substance seems to be free from phosphorus, and hence 

 contains no nucleins ; but it contains considerable sulphur (gen- 

 erally between 1 and 2 per cent.), which is readily split off. 

 Like casein, it contains no hetero-group (lack of heteroproteoses 

 on digestion), but differs in containing a carbohydrate group (in 

 small amount) and in the absence of phosphorus. On hydrol- 

 ysis Magnus-Levy l obtained glutaminic acid, tyrosin, and 

 1 Zeit. physiol. Chem., 1900 (30), 200. 



