OTHER RHYTHMS OF THE ORGANISATION 79 



In examining the diagram we easily see that from 

 the second to the third segmentation, a, b, c, there 

 exists a fixed law for the arrangement of the planes 

 of segmentation (O. Hertwig). The planes of 

 segmentation always cut one another at right angles, 

 so that they may be of equal size. 



As we see, the organic architecture is subject to 

 exact principles which are understood better every 

 day, as the intelligence is imbued with the know- 

 ledge of Nature. When they seem not to be regular, 

 it is because they are not known, as man has not 

 been able to penetrate the mechanism which 

 underlies them. 



Blastula (fig. 19). The pluricellular germ called 

 morula arrives at the moment when a cavity, called 

 a cavity of segmentation, begins to form in its 

 centre. In this cavity appears a liquid which, as 

 it increases, permeates the cells to the periphery, 

 until the pressure puts them in a lineal pattern in 

 the form of a circle. This form is known under 

 the name of blastula. A number of inferior animals 

 exist in this arrangement. This vesicle sometimes 

 presents vibrative cilia which cause a rotary move- 

 ment in the animal, and is called blastospheric. 



Gastrula. There comes a time when that portion 

 of the blastula marked with the letters cv bends 



