DIFFERENTIATION AND REJUVENATION 141 



here in the interior are lighter and darker spots. 

 These do not show very clearly in the picture, because 

 it is from a photograph of a living specimen under 

 the microscope. The lighter and darker spots corre- 

 spond to the details in the structure of the organism. 



B 



FIG. 51. Stentor cceruleus; A, cut into three pieces; B, regeneration of the first piece; 

 C, of the middle piece; D, of the posterior piece. After Gruber. 



Here is the tail of the organism, twisted, as you see, 

 and in life capable of being bent. The movement of 

 the animals in the natural fluid in which they are 

 suspended is quite active. Alongside are some blood 

 corpuscles; the figure is magnified about the same as 



