32 J. WILLIAM BUCHANAN 



These results suggest the possibihty that the developmental 

 processes of the X cells are stimulated by extremely dilute anes- 

 thetics. Numerous cases of stimulation of differentiation and 

 growth by weak solutions of anesthetics have been recorded 

 (Czapek, Biochemie der Pflanzen, Jena, '13, p. 159). 



The number of experiments thus far carried out is too small 

 to permit a more complete analysis of the results at this time, 

 and a more detailed consideration of the factors concerned in 

 the control of head frequency by this method and publication 

 of the data are postponed until further work has been completed. 

 The results so far obtained serve to show that head frequency 

 can be controlled by this method and that the effects of weak 

 solutions of anesthetics on head frequency are plainly non- 

 specific. 



Interesting results were obtained in measuring the rate of 

 oxygen consumption of pieces in weak solutions of anesthetics 

 throughout the two-week period of regeneration. In mol. 1/10 

 ethyl alcohol the rate of oxygen consumption of the pieces is 

 slightly higher than that of the control during the first day after 

 section. It continues to rise and at the end of two weeks is 

 more than 500 per cent the rate of the control in water. The 

 pieces in the alcohol solution lose slightly more weight than the 

 controls during the first two days after section, but thereafter 

 the pieces in the alcohol solution decrease in weight at the same 

 rate as the controls (six experiments). The rate of oxygen con- 

 sumption of pieces in mol. 1/800 chloral hydrate is approximately 

 the same as the rate of the controls during the first two days, 

 but on the third day it rises above that of the controls. It con- 

 tinues to rise, and at the end of two weeks is about 50 per cent 

 higher than that of the controls. The loss of weight takes 

 place at approximately the same rate in both controls and the 

 pieces in the chloral-hydrate solution (six experiments). The 

 rate of oxygen consumption of pieces in mol. 1/3000 chloretone 

 rises above that of the controls after four or five days, and at the 

 end of two weeks is about 20 per cent higher than that of the 

 controls. The loss of weight of the pieces in the chloretone 

 solution is shghtly greater during the first three days than that 



