110 THE THEORIES OF EVOLUTION 



found many partisans among the representatives of 

 the "evolutionist school." 



The problem of heredity can only be solved through 

 the study of the living matter, or protoplasm, con- 

 stituting the cell. Its properties, whether hereditary 

 or not, must necessarily depend upon its physico- 

 chemical composition. 



The chemistry of albuminoids and the properties of 

 colloids, the study of which is making great strides 

 and bids fair to explain many phenomena observed in 

 the living cell, are still very imperfectly known. 

 Most theories formulated in order to explain vital 

 phenomena, among them heredity, are based upon the 

 assumption that between the chemical molecules and 

 the organs of the cell, as revealed by the microscope, 

 there is another category of units, initial protoplas- 

 mic particles, which, by their characters and their 

 groupings, determine the various properties of living 

 matter. This idea is not new, for we can trace it back 

 to BufFon's theory of immortal particles which be- 

 come dissociated at death and can again form new liv- 

 ing combinations. It is now accepted by modern 

 thinkers and is apparently confirmed by Mendel's ex- 

 periments which were made some years ago, but have 

 only of late attracted the attention of the scientific 

 world. 



This theory, while it counts among its partisans the 

 great majority of scientists, has not yet been adopted 



