70 TRANSACTIONS AND PROCEEDINGS OF THK [Sess. LXV. 



rational laws inasmuch as they are not the result of 

 observation, but are deduced with mathematical precision 

 from the interpretation of cell division. 



The book concludes with two chapters of problems. 

 Chapter viii. deals with the analytical problems of cell 

 division. Having described in chapter vi. how cell 

 division would be completed under ideal conditions, in 

 these problems are determined the modifications pro- 

 duced by natural conditions. These problems thus deal 

 with the action on cell division of the position of the 

 central corpuscles, of gravity, of external mechanical 

 obstacles, of pressure, of the membrane, of adhesion, of 

 the physiological condition of cells of a cell aggregate. 

 These problems are mathematically set and solved by 

 mathematical formulas. 



The determination of the action of these various 

 conditions paves the way for the solution of the complex 

 problems of cell division — ^the determination of the segmen- 

 tation planes of all kinds of eggs when developed in natural 

 and under artificial conditions. 



Such is Giglio-Tos's theory, and undoubtedly the author 

 has done his work thoroughly. Every step is fully 

 elaborated, with the result that there is produced a 

 complete and symmetrical whole. When the results 

 arrived at theoretically are borne out by facts of observa- 

 tion, these the author has not failed to note, so that every 

 point is made to tell. As it stands, it affords new views 

 of the much debated subject of cell division, and gives 

 accuracy to conceptions of many physiological phenomena. 

 Whether all the results will be fully proved by the facts 

 of observation and experiment, and whether it gives us the 

 key to the mystery of life, time will tell. Among modern 

 materialistic and chemical theories of life, it must be 

 admitted as facile, princeps. 



One shuts the book with an appetite whetted for more, 

 and looks forward in anticipation and curiosity to the next 

 volume on ontogeny and its problems. 



