THE WONDER OF LIFE 481 



Simulacra Vitae. Biitschli, following Quincke, showed 

 how mimic cells might be produced by putting drops of 

 fine emulsions in suitable media. Some old olive oil beaten 

 up with a little powdered potassium carbonate forms a 

 very fine emulsion an acid in the oil attacking the salt 

 and liberating microscopic vacuoles of carbon dioxide. 

 The resulting emulsion is a microscopic foam, and micro- 

 photographs of drops of it look like micro-photographs 

 of some kinds of cells. For a time this resemblance gave 

 corroboration to the view that the minute structure of 

 cell-substance or cytoplasm was of the nature of a very 

 fine foam or emulsion, though of course made of very much 

 more complex materials than olive oil. It cannot be said, 

 however, that recent histological research has given support 

 to this interpretation. 



It is doubtful whether these simulacra vitse throw much 

 light on the structure and activity of living cells, though 

 it is quite probable that they may have a bearing on the 

 formation of non-living bodies made by organisms, such 

 as shells and pearls, spicules and calcareous corpuscles. 

 If a weak solution of gelatine is spread on a slide and tiny 

 drops of ferrocyanide of potassium are put on at intervals 

 of five millimetres or so, the result is the production of 

 rather striking simulacra of nucleated cells. But do these 

 simulacra in relatively simple material throw much light 

 on the structure of vital units ? They are as remote as 

 concentrically laminated agates are from tree-stems, as 

 remote as the beautiful dendritic growths of manganese 

 dioxide are from zoophytes. 



Professor Stephane Leduc has given much time to the 

 study of wonderful inorganic growths which he is able to 

 induce, and they certainly show what complex and beauti- 



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