126 JAMES I. ABBOTT ANM> I IIII'.L L. UK HARD-. 



a straight line- without the characteristic twitching of the cud-. 

 The worm- ^n>\\ more and more impotent until at la-t iu- 

 Stead of -wimminii directly towards the surface as i- usually the 

 case, they swim in a hapha/ard m.inucr and in spite of instinctive 

 efforts to reach the top of the water are unable to advance more 

 than an inch or two, falling back towards tin- bottom with 

 ever\ effort . This may be due to decrea-cd vitalit y but max also 

 be due t<> a greater \\ei.nht oil a<-count of the imbibition of water. 

 Repetitions ol the.-c experiments have confirmed the results in 

 every instance. Experiments have been undertaken to determine 

 what ions control or effect the permeability of the cuticle to 

 the water. 



Si \t\t \KV. 



1. Anguillula <u~cti succumbs in six days to very pure water 

 free from electrolytes when-a- in ordinary distilled water it \\ ill live 

 for much longer periods. 



2. The toxic qualities of the pure water appear to reside in 

 its solvent effect on the normally resistant cuticle of the worm 

 which is rendered much more permeable to water. 



3. Death is accompanied by physical manifestations suggestive 

 of great imbibition of water by the tissues. 



4. The presence of electrolytes in the medium, derived either 

 from solution of the glass culture tube or carried by "impure" 

 samples of distilled water, prolongs the life of the organisms in 

 <|iicMion, apparently by preserving the character of the membrane 

 so that the tissues will not imbibe water. 



