On the Nervous System of Cassiopea Xamachana. 



149 



INFLUENCE OF THE SENSE-ORGANS ON THE LOSS IN WEIGHT 



DURING STARVATION. 



The influence of the sense-organs on the rate of regeneration is so 

 clearly marked when muscular activity is excluded as the determining 

 factor that it seemed apparent that other metabolic activities might be 

 used as a measure of this influence. 



Mayer (1914) has shown that when Cassiopea is starved in sea- 

 water from which all food material has been removed by either careful 

 filtration or by heating to 71 C. and restoring by distilled water the 

 amount lost by evaporation, the loss of weight follows a course which 

 can be expressed mathematically by the formula yw(\ a)x, in 



.JOa 



90 



80 



70 



60 



50 



o = 



FIG. 10. Showing loss in weight of active and inactive half-disks during starvation. 

 (Compare table 9.) The divisions along the ordinate represent percentages of 

 the original weight ; those along the abscissa represent time in days. 



which y = the weight on any given day, w the original weight, x the 

 number of days' starvation, and a constant, "the coefficient of negative 

 metabolism." The greater part of the loss in weight appears to be 

 borne by the mesogloea, since this tissue constitutes by far the greater 

 bulk of the body, as is shown by histological examination of the 

 tissues and chemical analysis of medusse before and after starvation. 

 The simple character of the law which governs the loss of weight in 

 Cassiopea during starvation also indicates that substances of the 

 same sort serve to maintain the medusa throughout nearly the entire 

 course of starvation. As the result of starvation the cells become 

 reduced in size, some degenerate and disappear, while at the same 

 tune the mesogloea becomes highly vacuolated. Within the short 

 period of tune covered by these experiments very little histological 

 change could be recognized in the cells. The change in the appearance 



