r BIOLOGY, PHYSICS AND CHEMISTRY 35 



goes along with pure mechanism, and where they part 

 company. 



Imitation of the living by the unorganized may, 

 however, 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 

 protoplasmic 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 in 

 volving 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 obtained draw apart, attract the broken 

 and doubled ends of the filament of which the original 

 nucleus mainly consisted, and join them to form two 

 fresh nuclei about which the two new cells are con 

 structed 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, the air is 

 extracted from an alveolus, a cone of attraction is seen 

 to form, like those about the centrosomes which result 

 in the division of the nucleus. 2 Even the external 



1 Biitschli, Untersuchungen uber mikroskopische Schfiume und das Proto 

 plasma, Leipzig, 1892, First Part. 



2 Rhumbler, &quot;Versuch einer mechanischen Erklarung der indirekten 

 Zell- und Kernteilung&quot; (Roux s Archi&amp;lt;v, 1896). 



