METABOLIC GRADIENTS 57 



frog, for example, which is bilaterally symmetrical and 

 in which three axes, the major or longitudinal axis and the 

 minor transverse and dorso-ventral axes, are distinguish- 

 able in the arrangement of parts, disintegration begins 

 first of all at the anterior end and proceeds posteriorly, 

 and at any level of the body it begins in the median 

 dorsal region and proceeds laterally and ventrally. 



The susceptibility gradients in particular organs or 

 parts of the body also show a relation to the axes of these 

 parts. In the elongated tentacles of hydra and various 



Figs. 8, 9.— ^Axial susceptibility gradient of starfish egg in cyanide 



sea-anemones, for example, death begins at the tip and 

 proceeds toward the base, and in nerves, so far as exam- 

 ined, a susceptibility gradient exists and death proceeds 

 in the direction of conduction. 



Many other examples might be cited to show the 

 relation between the progress of death over the body 

 and the axes with reference to which an order in the 

 course of development, the arrangement of parts, or the 

 behavior of the organism can be distinguished. For the 

 present, however, it must suffice to say that the results 



