PROTEIDS. 749 



If the proteoses have been precipitated from a larger portion of urine by 

 ammonium sulphate, this precipitate is tested for the presence of different pro- 

 teoses for the reasons given in Chapter III. The following serves as a preliminary 

 determination of the character of the proteoses present in the urine. If the urine 

 contains only deuteroproteose it does not become cloudy on boiling, does not give 

 HELLER'S test, does not become cloudy on saturating with NaCl in neutral reaction,, 

 but does become turbid on adding acetic acid saturated with this salt. In the 

 presence of only protoproteose the urine gives HELLER'S test, is precipitated even 

 in neutral solution on saturating with NaCl, but does not coagulate on boiling. 

 The presence of heteroproteose is shown by the urine behaving like the above 

 with NaCl and nitric acid, but shows a difference on heating. It gradually becomes 

 cloudy on warming and separates at about 60 C. a sticky precipitate which 

 attaches itself to the sides of the vessel and which dissolves at boiling temperature 

 on acidifying the urine ; the precipitate reappears on cooling. 



In close relation to the proteoses stands the so-called BENCE-JONES- 

 proteid, which occurs in the urine in rare cases in diseases with changes 

 in the spinal marrow. It gives a precipitate on heating to 40-60 C. r 

 which on further heating to boiling dissolves again more or less completely, 

 depending upon the reaction and upon the amount of salt present. It 

 does not separate on dialysis, but can be precipitated from the urine by 

 double the volume of a saturated ammonium-sulphate solution or by 

 alcohol. It has also been obtained as crystals (GRUTTERINK and DE 

 GRAAFF, MAGNUS-LEVY). This body shows a varying behavior in 

 the different cases in which it has been found and its nature has 

 not been explained. From the investigations of the above-mentioned 

 and other experimenters (MOITESSIER, ABDERHALDEN and ROSTOSKI) 

 we can draw the conclusion that this proteid is similar to the proteoses 

 in several reactions, but that nevertheless it stands close to the genuine 

 protein bodies. It also yields primary as well as secondary proteoses 

 on peptic digestion (GRUTTERINK and DE GRAAFF), and yields the same 

 hydroiytic cleavage products as the other proteins (ABDERHALDEN and 

 ROSTOSKI) . l 



Quantitative Estimation of Proteid in Urine. Of all the methods pro- 

 posed thus far, the COAGULATION METHOD (boiling with the addition of 

 acetic acid) when performed with sufficient care gives the best results. 

 The average error need never amount to more than 0.01 per cent, and it 

 is generally smaller. With this method it is best to first find how much 

 acetic acid must be added to a small portion of the urine, which has been 

 previously heated on the water-bath, to completely separate the pro- 

 teid so that the filtrate will not respond to HELLER'S test. Then coagulate 

 20-50-100 cc. of the urine. Pour the urine into a beaker and heat on 

 the water-bath, add the required quantity of acetic acid slowly, stirring 

 constantly, and heat at the same time. Filter while warm, wash first 

 with water, then with alcohol and ether, dry and weigh, incinerate and 

 weigh again. In exact determinations the filtrate must not give HEL- 

 LER'S test. 



The separate estimation of GLOBULINS and ALBUMINS is done by carefully 

 neutralizing the urine and precipitating w r ith MgSO 4 added to saturation (HAMMAR- 



1 Magnus-Levy, Zeitschr. f . physiol. Chem., 30 (literature) ; Grutterink and de 

 Graaff, ibid., 34 and 40; Moitessier, Compt. rend. soc. biolog., 57; Ville and Derrien, 

 ibid., 62; Abderhal-.V:i :irnl Rostoski, Zeitschr. f. physiol. Chem.. 46. 



