SERALBUMINS. 255 



Seralbumiii differs from the albumin of the white of the hen's egg in 

 the following particulars: It is more levogyrate; the precipitate formed 

 by hydrochloric acid easily dissolves in an excess of the acid; it is rendered 

 less insoluble by alcohol. 



In preparing the seralbumin mixture, first remove the globulins, 

 according to JOHANSSON, by saturating with magnesium sulphate at 

 about 30 C. and filtering at the same temperature. The cooled filtrate 

 is separated from the crystallized salt and is treated with acetic acid so 

 that it contains about 1 per cent. The precipitate formed is filtered off, 

 pressed, dissolved in water with the addition of alkali to neutral reaction, 

 and the solution freed from salt by dialysis. The mixture of albumins 

 may be obtained in a solid form from the dialyzed solution either by 

 evaporating the solution at a gentle temperature or by precipitating 

 with alcohol, which must be quickly removed. STARKE 1 has suggested 

 another method, which is also to be recommended. The crystalline 

 seralbumin may be prepared from serum freed from globulin by half 

 saturating with ammonium sulphate, by the addition of more salt until 

 a cloudiness appears, and then proceeding according to the suggestion of 

 GURBER and MICHEL. On acidification with acetic acid or sulphuric 

 acid the crystallization may be considerably accelerated. 2 In the detec- 

 tion and quantitative estimation of seralbumin, the filtrate from the 

 globulin precipitated with magnesium sulphate can be heated to boil- 

 ing, after acidifying with a little acetic acid if necessary. The quan- 

 tity of seralbumin is best calculated as the difference between the total 

 proteins and the globulin. 



Summary of the elementary composition of the above-mentioned and de- 

 scribed proteins (from horse-blood) : 



C H N SO 



Fibrinogen 52 . 93 6 . 90 16 . 66 1 . 25 22 . 26 (HAMMARSTEN) 



Fibrin 52 . 68 6 . 83 16.91 1.10 22 . 48 " 



Fibrin-globulin 52 . 70 6 . 98 16 . 06 " 



Serglobulin 52.71 7.01 15.85 1.11 23.32 



Seralbumin 53.08 7.10 15.93 1.90 21.96 (MICHEL) 



Proteose-like substances have been found in blood-serum by several 

 investigators, and NOLF 3 has shown that after the abundant introduction 

 of proteoses into the intestine, they pass into the blood. BORCHARDT 4 

 has also been able to show that not only after the introduction of elastin- 

 proteose per os, but also after feeding dogs with not overabundant 

 quantities of elastin, a proteose, hemielastin, passes into the blood and 

 indeed can be eliminated by the urine. The question whether the pro- 

 teoses are normal constituents of the blood under ordinary conditions 

 is still much disputed. The difficulty in deciding this question lies in 



1 Johansson, Zeitschr. f. physiol. Chem., 9; K. Starke, Maly's Jahresber., 11. 



2 See Hopkins and Pinkus, Journ. of Physiol., 23; Krieger, Ueber die Darstellung 

 krystallinscher tierischer Eiweissstoffe, Inaug.-Dissert. Strassburg, 1899. 



3 Bull. Acad. Roy. Belg., 1903 and 1904. 



4 Zeitschr. f. physiol. Chem., 51 and 57. 



