ACTIONS AND USES 685 



partial vacuum. Glue, a coarse variety of gelatin, is made 

 from similar materials, less carefully purified ; size is an 

 inferior, weaker variety of glue ; isinglass, a natural colour- 

 less gelatin, is prepared from the air-bladder of the sturgeon, 

 and various species of Acipenser ; ehondrin is the gelatinous 

 matter extracted from cartilage ; ossein, the title given to 

 that obtained from bones. Gelatin, when dried, is hard and 

 tough ; varies in colour according to its purity ; forms a 

 viscid, tremulous mass, even when one per cent, is dissolved 

 in water and allowed to cool ; and is precipitated from 

 watery solutions by tannic acid. Gelatin is insoluble in 

 alcohol, and ether. It dissolves in acetic acid. 



ACTIONS AND USES. Gelatin, although a product of the 

 disintegration of albuminoid tissues, does not build up the 

 albuminoid or even the gelatinous tissues ; but being 

 tolerably easily digested, it appears to economise the more 

 valuable albuminoids. Men, dogs, and even horses, re- 

 covering from exhausting diseases, in which disintegration 

 and excretion of proteids is great, exhibit the dietetic 

 value of gelatin when it is given as soup, with fats or 

 carbo-hydrates. As a demulcent it has the disadvantage of 

 becoming hard and dry, and hence is not very suitable as 

 a permanent sheathing for irritable surfaces. Gelatinised 

 serum, consisting of fifty parts sterilised gelatin, ten parts 

 calcium chloride, and a thousand parts of water, is used as a 

 local haemostatic ; and for internal haemorrhage a solution 

 of eighty grains white gelatin, in seven to nine ounces of 

 sterilised sodium chloride solution (7 per 1000), may be em- 

 ployed hypodermically in doses of ij. to gviij. for horses ; 

 and 3ij- to j. for dogs. 



Glue, mixed with an antiseptic, is employed for securing 

 the broken horns of cattle, and occasionally for making 

 adhesive plasters. For closing wounds, where sutures 

 cannot be used, two pieces of stout cloth are cut so as to 

 leave a number of tails with uncut margins of several inches, 

 and are smeared with melted glue, usually mixed with pitch, 

 and applied, one on either side of the wound, with the uncut 

 margins towards each other. When the plaster is dry, 

 the uncut margins are sewed together, while, to prevent 

 displacement from movement of the skin, narrow strips of 



