78 SENESCENCE AND REJUVENESCENCE 



of recording the course of death and disintegration has proved to 

 be that of examining the lots of animals at stated intervals, e.g., 

 every half-hour, and recording the condition of each individual. 

 In order to accomplish this most readily five stages of disintegra- 

 tion have been more or less arbitrarily distinguished as follows: 



Stage I. Intact, not showing any appreciable disintegration. 

 Such animals or pieces are always alive and show movement. 



Stage II. In whole animals from the first appearance of disin- 

 tegration, which is practically always in the head-region, to the 

 first appearance of disintegration of the lateral margins of the body. 

 In pieces, from the beginning of disintegration at one or both ends 

 to the first appearance of disintegration on the lateral margins. 

 Considerable motor activity may still be present. 



Stage III.' In both whole animals and pieces from the appear- 

 ance of disintegration on the lateral margins until it has extended 

 over the whole length of the margins. Movement may still occur 

 in the parts least affected. 



Stage IV. From the end of Stage III to the time when the sur- 

 face of the body in the median regions disintegrates. iMotor 

 activity ceases. 



Stage V. Disintegration has extended to all parts of the sur- 

 face and the progress of death over the body is completed. The 

 remaining parts representing the internal organs gradually swell 

 and break up, but the process is not followed beyond the completion 

 of surface changes. 



Attention must be called to the fact that these stages represent 

 primarily the progress of the surface changes over the body from 

 one region to another rather than the progress of disintegration 

 through the internal organs. In these and other naked animals 

 differences in size of the animal do not aft'ect the progress of the 

 surface changes, while they may be an important factor in the rate 

 of penetration of the reagent and consequently in the disintegra- 

 tion of the internal organs. But since the surface changes in any 

 region are practically coincident with the death of that region, it is 

 not necessary to follow the internal changes, and in naked-bodied 

 animals the method becomes for all practical purposes independent 

 of size. 



