ii6 



BIOLOGICAL LECTURES. 



cration are so exactly parallel that one cannot fail to see at 

 once that the formative forces operate in essentially the same 

 manner with the one-celled as with the many-celled organism. 

 Gruber's experiment, as described in his recent article, "■Micro- 

 scopic Vivisection'' (Berichte der Naturforschenden Gesellschaft 

 zu Freiburg, Vol. VII, Part i, 1893), illustrates well this point. 

 A Stentor was cut into three pieces, A, B, C, each of which 

 regenerated the missing parts within 24 hours. The anterior 



yi 



fc 



Fu;. I. — Regeneration «f a Stentor cut into iliree parts. ./, />", C. rr = pulsating 



vacuole. 6"= regenerating frontal lieUl. 



end regenerated posterior end, and 7>icc versa. The middle 

 jiiece regenerated both ends — the comj^licated frontal field 

 with its mouth, ])har\nx, long cilia, ]-)u1sating vesicle, etc., as 

 well as the sini])lei' posterior region. 



Treat a ll\clra in the same wa\' \\\u\ similar results will follow. 

 In both cases the orientation of the parts will remain the same 

 as that of the whole. Gruber repeated the division of Stentor 

 four times in succession, getting perfect regeneration each 



