A DYNAMICAL HYPOTHESIS OF INHERITANCE. 37 



apparently normal character. But this result is fatal to the 

 ordinary corpuscular hypotheses, according to which every 

 future part is represented in the chromosomes by certain hypo- 

 thetical corpuscular germs. It has, indeed, been shown by Loeb 

 that larval development of portions of an egg can go on whether 

 the division be equal or unequal or in any radius. This seems to 

 indicate that an egg is not necessarily isotropic in the undivided 

 state, but that the moment that separation of its mass has 

 occurred there is a readjustment of the relation&and potentiali- 

 ties of its molecules simulating that of the original entire egg. 

 The very definition of isotropy, as given by one author (Lord 

 Kelvin), states that it may be assumed only of a spherical 

 mass of matter whose properties are absolutely the same along 

 every one of the infinite number of radii drawn from its center 

 outward, and, as tested by any means whatsoever, shows that 

 such a condition cannot be assumed, on the ground of observa- 

 tion alone, of any known egg. The condition of the egg we must/ 

 therefore also assume from its known properties to be aeolo-J 

 tropic, or different along every one of the infinite number on 

 radii drawn from its center. When we make this assumption, 

 however, we need not necessarily assume that nucleated frag- 

 ments that will still develop into larvae after division of the 

 oosperm, natural or artificial, must be isotropic. They may be 

 aeolotropic from the beginning, but in precisely the same way 

 in each case, as a result of the successive cleavages of the 

 germ-mass, by means of planes that cut each other at right 

 angles, as in the diagram Fig. I, where each of the four seg- 

 ments are precisely alike from the pole 

 a to that of b. The unlikeness of the 

 pole a from b is indicated by the stip- 

 pling. This unlikeness would mani- 

 festly be unimpaired by segmentation 

 of the germ into four quadrants by the 

 first two cleavages, as shown in the 

 diagram. The same might hold of oct- 

 ants of the spherical germ. Here the 



initial aeolotropy of the whole egg determines that of its seg- 

 ments ; that must therefore become four or eight molecular 



