437 



fers is perfectly preserved, so that details of structure can be studied 

 with great ease and thoroughness. By bringing about a considerable 

 degree of narcosis in earthworms and fresh-water mussels in a short 

 time Chloretone lessens the time hitherto needful for the preservation 

 of these animals in an extended condition. 



In the following experiments Chloretone was used in solution in 

 spring water in the proportions of 1 : 100 (in which not all the crystals 

 are dissolved), 1 : 200, 1 : 300, 1 : 1000, 1 : 1500, 1 : 2000, and 1 : 5000. 

 One set of experiments made with distilled water yielded results simi- 

 lar to those obtained with spring water. 



These solutions were used upon Amoeba, Paramaecium, Hydra 

 (green and brown), Planaria, Oligochaeta, Rotifera, Mollusca (snails 

 and fresh- water mussels), Crustacea (Daphnia, Ostracods, Copepods) 

 and Tadpoles. 



Amoeba. In solutions of 1 : 100 and I : 200 the amoebae con- 

 tracted into balls. In 1 : 300 and 1 : 1000 the formation of pseudopodia 

 was accentuated, but the rate of movement remained the same. 



Paramaecium: In even the weakest solutions that took effect 

 the paramoecia remained contracted. 



Hydra. H. viridis was at first not affected by the weaker solu- 

 tions, while in the stronger (1 : 100, 1 : 200, 1 : 300) it was strongly 

 contracted. After 18 hours in the solution of 1 : 1000 there was slight 

 contraction and beginning of maceration in the tentacles. In 1 : 1500 

 and the weaker solutions there was a slight degree of contraction and 

 a little movement. 



H. fuse a (?) in solutions of 1 : 100, 1:200 and 1 : 300 became at 

 once greatly contracted and the contents of the digestive cavity were 

 ejected. The animals then began to disintegrate. In this way fine 

 maceration preparations can be obtained. 



The solution of 1 : 2000 caused the greatest extension. After 

 eleven days the hydras in the solution of 1 : 1000 were dead and their 

 tentacles were falling to pieces. In the solutions of 1 : 1500, 1 : 2000 

 and 1 : 5000 the hydras were still living and on treatment with hot 

 mercuric chloride they all contracted slightly, the contractility being 

 greatest in those in the weakest solution. They were, however, fixed 

 in a relatively extended state; and sections show that the endoderm 

 cells are much less vacuolated than after treatment with some other 

 anaesthetics. 



Planaria. In the strong solutions the worms were greatly con- 

 tracted, while in the weaker solutions they became after the first in- 

 stant greatly relaxed and soon began to disintegrate. In the solution 



