OSMOTIC GROWTH 



125 



membranous covering for itself. Tin's is the explanation of 

 the fact that all living organisms are formed bv colonies of 

 microscopical elements, although we must not forget that 

 Nature often produces similar 

 results in different ways. 



Osmotic growths may be 

 obtained from a great number 

 of chemical substances. The 

 most easily grown are the 

 soluble salts of calcium in 

 solutions of alkaline phos- 

 phates and carbonates, to 

 which we have already al- 

 luded. We may also reverse 

 the phenomenon bv growing 

 phosphates and carbonates 

 in solutions of calcium salts. 

 but in this case the osmotic 

 growths are not so beautiful. 



The various silicates play 

 an important part in the con- 

 stitution of shells and of the 

 skeletons of marine animals. 

 Most of the metallic salts, and 

 more especially the soluble 

 salts of calcium, give rise to 



Osmotic grow ths ol fenocyanide' of 

 copper. 



the phenomenon of osmotic 

 growth when sown in solutions 

 of the alkaline silicates. In this way, bv using different 

 silicates and varying the proportions and the concentra- 

 tions, we may obtain an immense variety of osmotic 

 growths. 



A good solution to commence with is the following: — - 



Silicate of potash, sp. gr. 1*3 (33' Beaume) . . 60 gr. 



Saturated solution of sodium carbonate . . 60 gr. 



Saturated solution of dibasic sodium phosphate . 30 gr. 

 Distilled water .... make up to I litre. 



