VITAL FORCES. 27 



preponderate over the loss ; and hence, from birth to 

 maturity, there is not only a rapid circulation of the 

 vital fluid through the system, deposited everywhere 

 from its stores, but a rapid reception and assimilation 

 of extraneous matter, and, accordingly, an unceasing 

 demand for aliment. 



There is, it may be observed, a remarkable 

 attraction through an animal or vegetable membrane, 

 of a thin fluid by one that is denser. Thus, 

 Dutrochet found that if he filled the swimming 

 bladder of a carp with thin syrup, and placed it in 

 water, the bladder gained weight by attracting 

 water through its sides. To this he gave the name 

 of Endosmose, from two Greek words, from the 

 principal current flowing inwards. He also dis- 

 covered that if he filled the same bladder with 

 water and placed it in thin syrup, it lost weight, 

 its contents being partially attracted through the 

 sides into the surrounding syrup ; and this, from 

 the flow being outwards, he called Exosmose. The 

 same result occurred in the transmission of fluids 

 through the tissue of plants. It was found possible 

 to gorge parts of vegetables with fluid by merely 

 placing them in water, and to empty them again 

 by rendering the fluid in which they were placed 

 more dense than that which they contained. 

 Dutrochet says, that water thickened with sugar in 

 the proportion of 1 sugar to 2 water, produced a 

 power capable of sustaining a column of mercury of 

 127 inches, or the weight of 4J atmospheres. 



