448 THE GLANDULAR ORGANS. 



Ovalbumin. The amount of crystallizable ovalbumin which can 

 be obtained from white of egg varies between 30 and 40 grammes 

 pro liter. The limits of precipitation of the substance, when 

 purified carefully arid brought into a 10 per cent, solution, containing 

 the normal amount of alkali of white of egg, viz., 0.225 gramme 

 of sodium carbonate for 100 grammes of albumin, were 62 and 68. 

 Elementary analysis of a carefully purified preparation gave the 

 following results (Langstein) : C = 52.46 ; H = 7.19 ; N = 15.29 ; 

 S= 1.34 ; and O = 23.72. On hydrolysis with baryta ovalbumin 

 yields a polymeric nitrogenous carbohydrate, which S. Friinkel has 

 termed albamin, and which appears to be an acetylated glucosamin. 

 Seemann and Langstein could both demonstrate the formation of 



flucosamin on hydrolysis with dilute acids. The formula which 

 Vankel suggests for his albamin is 2(C 6 H 9 O 4 NH 2 ) -f- H 2 O. 



Conalbumin. Whether the conalbumin is in reality a unity and 

 not a mixture of two or more bodies is uncertain. Elementary 

 analysis has given the following results (Osborne and Campbell) : 

 C 52.25; H = 6.99 ; N = 16.11; S=1.7; O = 22.95. Ac- 

 cording to Langstein, the substance is free from phosphorus. Like 

 all the other albumins of white of egg, the conalbumin also yields 

 glucosamin on hydrolytic decomposition. It appears, as Hofmeister 

 suggests, that the glucosamin in the white of egg fulfils the same 

 object as the milk-sugar in the case of milk. 



Analysis of the Albumins of White of Egg. The whites of 

 a large number of eggs are freed from their membranes by beat- 

 ing; the material is filtered and the filtrate treated with an equal 

 volume of an accurately neutral solution of ammonium sulphate. 

 (Care should be had that only such eggs are used which present an 

 alkaline reaction with litmus.) After standing for one-half hour 

 the precipitated globulins are filtered oif. The clear filtrate, which 

 usually presents a reddish color, is now treated with one-fifth 

 normal solution of sulphuric acid until the fluid becomes opaque. 

 If anv crystals of ovalbumin are available, a few are added to 

 hasten crystallization. This, however, is not necessary. The solu- 

 tion is allowed to stand, when gradually a separation of crystals of 

 ovalbumin will occur. The best results are obtained if the tempera- 

 ture of the room is not less than 15 C. ; in a cold room no result 

 is usually gotten. To purify the crystals, a feebly acid solution of 

 ammonium sulphate is used, crystallization being hastened by inocu- 

 lation with a few crystals of the substance. After standing until 

 crystals cease to separate out, and after they have been removed, 

 the remaining solution is dialyzed against running water until the 

 sulphuric acid has been almost entirely removed. It is then heated 

 on a water-bath until all coagulable material has separated out. 

 This is filtered oif and thoroughly washed with hot water until the 

 filtrate is free from sulphuric acid, and no longer gives a cloud with 

 phosphotungstic acid. The resulting substance is dried at 110 C. 

 and represents the conalbumin. 



