CHAPTER IX 



THE ALBUMINS PROPER 



WHEN we read in older descriptions about 'albumins/ and especi- 

 ally about their physical properties, we must remember that the 

 simple coagulable albumins are meant, or, in other words, what we 

 now call " the albumins proper " and the globulins. 



I. THE ALBUMINS 



Two albumins are known : serum-albumin and lact-albumin, but 

 it is customary to also include egg -albumin, although the latter 

 ought to be classified amongst the glycoproteids. How these albu- 

 mins differ from one another in different animals has been discussed 

 on pp. 355. 360, 361, 363, etc. 



Albumins are coagulable substances, which are soluble in salt- 

 free water. The author's view as to why albumins are soluble in 

 salt-free water is given on p. 295. Their pure solutions have a 

 neutral reaction. As a rule, they are less readily precipitable than are 

 the globulins and many of the proteids, and this circumstance is made 

 use of in isolating them. They are not rendered insoluble by coming 

 into contact with animal charcoal or with porous earthenware as 

 is, for example, caseinogen, and therefore they may be filtered 

 through porous plates without being precipitated. 



They are not precipitated by saturating their neutral solutions, 

 even at 40 , 1 with sodium chloride 1 or with magnesium sulphate, 2 

 while, according to Schafer 3 and Starke, 4 they are thrown down by 



1 J. Lewith, Arch./, experiment. Path, und Pharm, 24. 1 (1887). 



2 Tolmatscheff, Hoppe-Seylers med.-chem. Untersuchungen, p. 272 (1867) ; 0. Ham- 

 marsteu, Zeitschr.f. physiol. Chem. 8. 467 (1884) ; E. Johanusson, ibid. 9. 310 (1885) ;. 

 J. Lewith, Arch. f. experiment. Path, und P/iarm. 24. 1 (1887) ; K. V. Starke, 

 Maly'sJahresber.f. Tierchem. 11. 17 (1881). 



3 E. A. Schafer, Journ. of Physiol. 3. 181 (1880). 



4 K. V. Starke, Maly'sJahresber.f. Tierchem. 11. 17 (1881). 



353 2 A 



