NILE BLUE SULFATE AS VITAL STAIN ON HYDRA. 



221 



process of reconstitution of the pieces the blue color was found 

 confined to the original colored cells or the new cells derived 

 from this group as the following example will serve to illustrate. 

 An animal was stained as described above and a piece removed 

 by two parallel cuts, transverse to the longitudinal axis of the 

 animal (Fig. I, ab). This cross-section, when removed from the 

 animal, appeared as a ring of tissue with the blue spot (stippled 

 area) at one point in the circumference (Fig. 2). This ring of 

 tissue was then divided into two equal portions by a cut (Fig. 

 2, cd) which passed through the blue spot. The two pieces were 

 allowed to reconstitute and at the end of four days two small 

 animals were found similar in marking to Fig. 3. 



The process of reconstitution was as follows: the two cut 

 lateral ends of each semicircle had approached and fused, thus 

 forming two small rings similar to that seen in Fig. 2. Further 

 process of reconstitution had then ensued governed by the 

 original polarity of the pieces as is indicated by the color pattern 

 as seen in Fig. 3. Further application of this staining method 

 has been made in investigations not published as yet. 



