128 THE MECHANISM OF LIFE 



The calcium chloride surrounds itself with an osmotic 

 membrane ; water penetrates into the interior of the cell thus 

 formed, and a beautiful transparent spherical cell is the result, 

 the summit of which soon emerges from the shallow liquid. 

 The cell continues to increase by absorption of the liquid at 

 its base, and may grow up out of the liquid into the air for 

 as much as one or two centimetres. 



This is a most impressive spectacle, an osmotic production, 

 half aquatic and half aerial, absorbing water and salts by its 

 base, and losing water and volatile products by evaporation 

 from its summit, while at the same time it absorbs and 

 dissolves the gases of the atmosphere. 



The aerial portion of an osmotic growth will sometimes 

 become specialized in form. The summit of the growth 

 develops a sort of crown or cup surrounded by a circular wall. 

 This cup contains liquid, and continues to grow up into the 

 air like the stem of a plant, carrying with it the liquid which 

 has been absorbed by the base of the growth. 



The preceding experiments give us an explanation of the 

 curious phenomena exhibited by so-called creeping salts. A 

 saline solution left at the bottom of a vessel will sometimes lie 

 found after some months to have crept up to the top of the 

 vessel. Cellular partitions formed in this way will be found 

 extending from the bottom to the top of the vessel, and not 

 onlv so, but the whole of the remaining liquid will be im- 

 prisoned in the upper cells. 



Assimilation and Excretion. — Like a living being, an 

 osmotic growth absorbs nutriment from the medium in which 

 it grows, and this nutriment it assimilates and organizes. If 

 we compare the weight of an osmotic growth with that of the 

 mineral fragment which produced it, we shall find that tin 

 mineral seed has increased many hundred times in weight. 

 Similarly, if we weigh the liquid before and after the experi- 

 ment, we shall find that it has lost an equivalent weight. 

 The absorbed substance of an osmotic production must also 

 undergo chemical transformation before it can be assimilated — 

 that is, before il can form part of the growth. Calcium 

 chloride, for example, growing in a solution of potassium car- 



