108 ACTION OF SALTS. 



then liberated, it acts on the geate of lime, super- 

 geates result, and these are easily soluble. 



3d. The great use of lime is as a converter, 

 turning solid and insoluble geine, even solid vegeta- 

 ble fibre into soluble vegetable food. Here is the 

 point, where philosophy seems to give the choice, 

 to refer this action to one of the numerous cases of 

 catalytic change, which are every day becoming 

 more and more familiar; or to explain the whole 

 process by referring it to saponification. This word 

 is used as conveying at once what is meant, but it 

 is not meant to say that the product of lime and 

 vegetable matter is soap. The action of lime on 

 geine, may be similar to its action on oil and fat. 

 It is well established, that animal and vegetable oils 

 and fats, are converted into acids, by the action of 

 alkalies, earths, oxides, and even by vegetable fibre 

 itself. The general law is, that whenever a sub- 

 stance, capable of uniting with the acid of fat or oil, 

 is placed in contact with fat or oil, it determines the 

 production of acid. Now it has been shown, that 

 alkali produces a similar change on geine, it devel- 

 oped acid properties. If alkali has converted vegeta- 

 ble oil and geine into acid, it is a reason why 

 a similar action may be produced by all those 

 substances which act thus on oil. Hence lime, 



