1.1 BIOLOGY, PHYSICS AND CHEMISTRY 33 



so perhaps the integration of the physico-chemical ele- 

 ments of properly vital action might determine that action 

 only in part — a part would be left to indetermination. 

 But such an integration can be no more than dreamed of; 

 we do not pretend that the dream will ever be realized. 

 We are only trying, by carrying a certain comparison as 

 far as possible, to show up to what point our theory goes 

 along with pure mechanism, and where they part company. 

 Imitation of the living by the unorganized may, how- 

 ever, go a good way. Not only does chemistry make 

 organic syntheses, but we have succeeded in reproducing 

 artificially the external appearance of certain facts of 

 organization, such as indirect cell-division and proto- 

 plasmic circulation. It is well known that the protoplasm 

 of the cell effects various movements within its envelope; 

 on the other hand, indirect cell-division is the outcome 

 of very complex operations, some involving the nucleus 

 and others the cytoplasm. These latter commence by 

 the doubling of the centrosome, a small spherical body 

 alongside the nucleus. The two centrosomes thus ob- 

 tained draw apart, attract the broken and doubled ends 

 of the filament of which the original nucleus mainly con- 

 sisted, and join them to form two fresh nuclei about which 

 the two new cells are constructed which will succeed the 

 first. Now, in their broad lines and in their external 

 appearance, some at least of these operations have been 

 successfully imitated. If some sugar or table salt is 

 pulverized and some very old oil is added, and a drop of 

 the mixture is observed under the microscope, a froth of 

 alveolar structure is seen whose configuration is like that 

 of protoplasm, according to certain theories, and in which 

 movements take place which are decidedly like those of 

 protoplasmic circulation. 1 If, in a froth of the same kind, 



1 Butschli, Untersuchungen iiber mikroskopische Schdume und das Pro- 

 toplasma, Leipzig, 1892, First Part. 



