200 W. E. ALLEX. 



excellent re-tilt- in staining, the muscles showing especially well. 

 Two adverse conditions must be kept in mind throughout the 

 consideration of this experiment. (l) Lack of ability to control 

 temperature evidently affected the rate of growth seriously as 

 indicated by Chart II. (2) The old tissue is it>elf so embryonic 

 in character that it is extremely difficult to make an accurate 

 measurement of the amount regenerated or an adequate descrip- 

 tion of its changing features. Some of the vagaries of the 

 polygon must be attributed to both these causes. General con- 

 ditioii> \\ere good as is shown by the fact of only one death in 

 tin- regular series. Drawings are omitted because the requisite 

 series is too complicated for a paper of this character. 



DATA . 



These descriptions are somewhat indefinite because the facts 

 themselves with few exceptions lack clear definition. 



P.v tlu- end of the first hour the epidermis had stretched over 

 and very nearly covered the cut surface. In six hours it showed 

 rapid proliferation, with cells closely and irregularly massed and 

 three or four deep. This condition remained much the same in 

 general appearance except for outward extension of the entire 

 mass at the end of the first day. In two days the older regen- 

 erated epidermis was indistinguishable from the neighboring 

 primary epidermis, though still proliferating at the tip. This 

 general condition remains unchanged to the tenth day which is 

 as far as the study of sections could be carried with any pretence 

 of general accuracy. 



The parenchyma showed some sign of reorganization in one 

 da\ and there was a considerable apparent difference on the 

 second day, but thereafter there was no appreciable difference 

 from the ordinary conditions. 



Bloodvessels were not in evidence in the regenerated tissue 

 until the second day when some were seen which \\ere e\ idently 

 functional almost to the distal extremity of the new tissue. Alter 

 the MO md day a fairly large vessel is uniformly found just 

 beyond the distal end of the ner\ e n>rd. and some capillaries 

 were identified (|iiite near the tip in almost all specimens. Many 

 of tllCM were easily ol>MT\able in the live specimen-. 



