490 VEGETABLE FIBRIN. 



white mass, which, in a moist condition, is tough and 

 elastic, in a dry condition, hard and brittle. It is in- 

 soluble in water, dilute hydrochloric acid, and in a so- 

 lution of sodium chloride, and swells up in the latter, 

 as well as in a solution of saltpetre. 



If the blood is allowed to flow from the vein directly 

 into a concentrated solution of sodium sulphate, the 

 precipitation of the fibrin is prevented ; if, however, 

 the solution is now poured or filtered off from the 

 blood-globules, and saturated with sodium chloride, 

 there is produced a flocculent precipitate, the aqueous 

 solution of which coagulates in a short time, as fibrin. 



A body, very similar to the fibrinogeiious and fibrino- 

 plastic substances, is globulin, in the crystalline lens. 

 It resembles these substances in nearly all its proper- 

 ties, but with neither of them does it form fibrin. A 

 neutral solution of globulin begins to grow turbid at 

 73, but is not coagulated below 93, when it also ex- 

 hibits an acid reaction. 



5. Vegetable fibrin. A protein compound is con- 

 tained in the different varieties of grain in a coagulated 

 condition ; it very strongly resembles animal fibrin. 

 It is obtained from flour, in largest quantity from 

 wheat flour, by mixing it with water, so as to form a 

 stiff dough, tying this up in a cloth, and then kneading 

 it for a long time in cold water, thus thoroughly wash- 

 ing out the soluble ingredients, starch and albumen. 

 It remains behind as a grayish-yellow, tough, pasty 

 mass, capable of being drawn out in thin layers 

 (glutin). Boiling alcohol extracts from it a sticky 

 substance (vegetable gelatin, glutin), likewise contain- 

 ing nitrogen, which, when dried, is brown and viscid ; 

 ether extracts a fatty oil. "When seeds sprout, this 

 protein compound is converted into a soluble sub- 

 stance, diastase, which has as yet not been prepared in 

 a pure condition. It is remarkable on account of its 

 property of converting large quantities of starch into 

 glucose, when dissolved in water, and heated to 50-70 

 (compare p. 194). 



