THE REPRODUCTIVE GLANDS. 425 



albumin. Alcohol and ether rapidly destroy their solubility. The 

 difference in their degree of rotation on polariscopic examination, 

 as compared with serum-albumin, is seen below : 



Serum-albumin a (D) 62.6-64.6 



Ovalburnin-a a (D) 33.1 



Ovulbumin-/? a (D) 53.6 



Ovalbumin-7 '. . . a (D) 70.8 



The coagulation-point of the three ovalbumins collectively, in a 

 0.3 per cent, solution, is at 56 C. That of the individual sub- 

 stances is given as 72 C., 76 C., and 82 C., respectively. The 

 elementary composition of the different forms is probably much the 

 same, and is represented by the following figures (Hammarsten) : C, 

 52.25; H, 6.90; N, 15.25; S, 1.67-1.93; O, 23.67-23.93 per cent. 



Hofmeister obtained the albumins in crystalline form by slow 

 evaporation of their solution in a dilute solution of ammonium sul- 

 phate. On fractional crystallization the different forms may then 

 be obtained. The crystals contained 0.55 per cent, of calcium phos- 

 phate, which is apparently present in molecular combination. 



ISOLATION. To isolate the ovalbumins conjointly, the albumen, 

 after separation from its membranes, is diluted with two and one-half 

 times its volume of water. A slight turbidity thus results, which is 

 filtered off. The liquid is saturated with magnesium sulphate in 

 substance at a temperature of 20 C., which causes precipitation 

 of the globulins. After filtration sodium sulphate is further added 

 to saturation, at the same temperature. The ovalbumins separate 

 out on standing. They are filtered off, dissolved in water, and freed 

 from salts by dialysis. On evaporation in a vacuum, at a tempera- 

 ture of from 40 to 50 C., they are obtained in pure form. 



To isolate the albumins in crystalline form, the albumen is 

 beaten to a froth and allowed to drip. The drippings are treated 

 with an equal volume of a saturated solution of ammonium sul- 

 phate, and freed from globulins by filtration. The filtrate is then 

 placed in a shallow vessel and is allowed to evaporate at the tem- 

 perature of the room. The material, which thus separates out is 

 dissolved in water, treated with a saturated solution of ammonium 

 sulphate until the solution becomes turbid, and is allowed to stand. 

 The resulting crystals can be purified by a repetition of the process. 



Globulins. The globulins of the albumen represent only about 

 7 per cent, of the total amount of albumin. Different forms appar- 

 ently exist, of which one is said to coagulate at 47 C. and another 

 at 67 C. They may be isolated as described above. 



Ovomucoid. The mucoid substance which can be isolated from 

 the albumen of hens' eggs is present in considerable amount, consti- 

 tuting about 10 per cent, of the total solids. According to Morner, 

 it contains 12.65 per cent, of nitrogen and 2.2 per cent, of sulphur. 

 On boiling with dilute mineral acids it yields a reducing substance, 

 which may be of the character of glucosamin, and is derived from a 

 chondroitin-sulphuric acid radicle. 



