VOLUME IN LIQUIDS. 57 



When a solution of sugar (1 part of sugar to 16 of 

 water) is separated by a bladder from water, it in- 

 creases in volume ; but if we add 1 part of oxalic 

 acid to the sugar, the water, on the contrary, in- 

 creases in volume. If the amount of sugar in the 

 solution be doubled, the liquids mix without change 

 of volume. A solution of sugar, separated by 

 bladder from one of oxalic acid, rises, in the same 

 time, 3 times higher than when separated from 

 water. (DUTROCHET.) 



From these experiments we obtain, as a universal Membranes 

 result (which, however, requires confirmation), that bk power" 

 an animal membrane possesses a less power of ab- fng^ouTtion 

 sorption for solution of albumen than for all other 

 organic substances; and that a small amount of Effect of 

 mineral or organic acids increases the power of adds, 

 transudation of water as well as of the solutions of 

 many organic substances.* 



The rapidity of mixture of two liquids, separated Causes 



( t which in- 



by a membrane, depends on the thickness of the fluence 

 membrane, and stands in direct proportion to the 



velocity with which the mixture formed in the 



* In order not to be misled in such experiments, we must avoid 

 the employment of all those liquids which alter the membrane in 

 its chemical properties. Such are, for example, acids of a cer- 

 tain concentration, nitrate of silver, salts of lead, chloride of 

 gold, chloride of tin, chromic acid, bichromate of potash, taunic 

 acid, &c. Even in water, the properties of membranes generally 

 undergo a change after some days, they then propagate a far 

 weaker hydrostatic pressure through their pores, and are no 

 longer fit for such experiments. 



