116 



C. M. CHILD 



fluid and covered with an accurately fitting glass plate, and the 

 fluid was renewed daily. At intervals of two days ten pieces 

 including the region between the levels 1 and 4 in figure 1 were 

 cut and allowed to regulate in 1.5 per cent alcohol. In the first 

 of these sets the worms had been in alcohol two days before the 

 operation, in the second set four days, etc. 



In general the series shows that the effect of the alcohol on regu- 

 lation increases with the length of time in alcohol before section, 



A 



10 



II 



12 



13 



Figs. 10 to 13 Alcohol. Figure 10, piece including region anterior to level 4 in 

 figure 1: regulation in alcohol 1.5 per cent. Figure 11, similar piece: regulation 

 in water. Figure 12, piece including region between levels I and J^ in figure 1: 

 from worm in alcohol 1.5 per cent two days before section: regulation in alcohol 

 1.5 per cent. Figure 13, similar piece from worm in alcohol four days before 

 section. 



the length of time after section being the same in all cases. Fig. 

 12 shows the characteristic condition of the pieces cut after the 

 worms had been two days in 1.5 per cent alcohol and allowed to 

 undergo regulation during fourteen days in alcohol of the same 

 concentration. Five pieces remained alive at the end of this 

 time and all were much alike. Tail-formation is almost com- 

 pletely inhibited but the pharynx is well developed though small. 



