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STUDIES IN ADVANCED PHYSIOLOGY. 



Fig. 6. SHOWING SOME OF THE STAGES IN THE DIVISION OF THE CELL. 



It is interesting to observe that simple animals, who 

 in comparison with the mammals, say, have but little that 

 is passed on to the succeeding form, show a much simpler 

 type of cell division. When we remember that in the 

 chromosomes of the egg there are housed in their finer 

 structure those determining influences which later on will 

 reappear in the shape, size, structure, coloration, intona- 

 tion of voice, and even instincts of a wonderfully com- 

 plicated adult individual, we are not surprised to see the 

 care with which the chromosomes are elaborated, for the 

 important purpose of producing a new cell. While it 

 explains in no sense the real cause of heredity, it is appar- 

 ent that in this process there is a valuable suggestion as to 

 the actuality of a physical basis for heredity. 



