344 SERGIUS MORGULIS 



during the period of the greatest per cent of water, coinciding 

 approximately with the period of the highest regenerative activity, 

 the organism loses practically no water. This will be better appre- 

 ciated by consulting diagrams 5 to 7, where the curve of water 

 content forms for a longer or shorter space either a horizontal 

 line or even an ascending one. The retention of water in the or- 

 ganism, resulting in a rapid rise of its relative content, may per- 

 haps have something to do with the properties of the regenerated 

 tissue. Soon after that the quantity of water commences to 

 diminish quite rapidly, so that the per cent of water again approx- 

 imates the normal. 



EXPERIMENTS ON DIEMYCTYLUS VIRIDESCENS' 



During the winter of 1909-10 I examined the content of water 

 in regenerated tails of the salamander Diemyctylus. The study 

 included only two stages in the regenerative process — at one month 

 and at three months after the operation. The results are, there- 

 fore, not sufficient to establish the complete curve of the per cent 

 of water, but in spite of this incompleteness I venture to add these 

 results because of their important bearing upon those previously 

 obtained on Podarke. In the case of Diemyctylus the regener- 

 ated tails were severed from the body and separately examined 

 for their content of water, which was then compared with the 

 water content of the old tail. The water content of the regener- 

 ating salamander itself was also determined in several instances, 

 and the per cent of water in its tissues was invariably found to be 

 normal. It is, therefore, certain from this investigation on 

 Diemyctylus that the changes in the water content were confined 

 to the regenerated tissue. 



From the tables 5 to 9 it can be seen that the quantity of water in 

 the regenerating tails is relatively much greater than in the old 

 tails, and furthermore that it is relatively greater in an early than 

 in a later stage of regeneration. It will be seen on looking through 

 table 9 that, whereas the old tails contained only 74.94 per cent of 



* These experiments were performed in the Zoological Laboratory of Harvard 

 University. 



