MOLECULES. 59 



tion and disintegration of fluid and solid substances by 

 chemical and mechanical action." Under the head of his- 

 togenetic molecules, Dr. Bennett describes the molecular 

 matter produced by an admixture of oil and albumen, and 

 shows how the latter may be caused to coagulate in the form 

 of a membrane on the surface. 



He considers that the molecules are formed by a phy- 

 sical process, and that afterwards they become aggregated 

 together, so as to form masses around which the cell-wall is 

 formed. According to these views, then, the living cell, 

 endowed with the power of forming peculiar substances, 

 and of producing other living structures like itself, originates 

 in much the same way as the artificial cell consisting of oil 

 and albumen with an insoluble envelope, which possesses 

 none of the powers characteristic of living cells, and can be 

 made artificially. The cell in the living body is formed by 

 the aggregation of living particles, the artificial cell by the 

 aggregation of lifeless particles. In each case the membrane 

 is supposed to be thrown around the collection, and the 

 " cell " is complete. 



It is true that a living " molecule " placed in a fluid con- 

 taining inanimate matter will grow, and will gradually assume 

 the appearance of a collection of molecules, but the growth 

 does not depend on the aggregation of a number of mole- 

 cules. The substances passing into the interior of the 

 original particle are in solution, and the molecular appear- 

 ance results from subsequent changes. Again, a number of 

 minute living particles being suspended in fluid never run 

 together and form collections. So far from aggregating 

 together, they divide and subdivide, and multiply enormously 

 in number. Inanimate particles, on the other hand, always 



