PHYSIOLOGY OF SYNAPTULA HYDRIFORMIS 



369 



gives none. If the concentration of the salts in sea-water is 

 taken as 5/8 M, (Mayer, '11, '14), then the former dilution cor- 

 responds to 1/2 M, i.e., a change of 1/8 M is sufficient to cause 

 a reaction. On the other hand, 6 cc. sea-water + 4 cc. sea-water 



TABLE 7 

 Limiting concentrations of chemical agents 



Sweet 



Sour 



Anaesthetics 

 Alkali 



Salts. 



REAGENT 



[Glycerine 



Sugar (cane) 



Saccharine 



Acetic acid 



Hydrochloric acid, 

 [Oxalic acid 



Alcohol 



Ether 



Ammonium hydrate 

 fNaCl 



KC1 



KBr 



CaCl 2 

 { MgCl 2 



NaS0 4 



KI 



NH 4 C1 



NaC 2 H 3 2 



RESPONSE TO 



1/2 M 

 1/2 M 

 1/200 M 

 1/400 M 

 1/600 M 

 1/200 M 

 1/5 M 

 1/100 M 

 1/200 M 

 1/4 M 

 1/40 M 

 1/40 .1/ 

 1/20 M 

 2/5 M 

 1/8 M 

 1/80 M 

 1/15 M 

 1/10 M 



NO RE- 

 SPONSE TO 



1/41 

 1/4 M 

 1/400 M 

 1/800 M 

 1/900 M 

 1/400 M 

 1/10 M 

 1/200 M 

 1/400 M 

 1/8 M 

 1/50 M 

 1/80 M 

 1/40 M 

 1/5 1 

 1/10 M 

 1/160 M 

 1/20 M 

 1/20 M 



TABLE 8 



Minimum concentrations of chemical agents which will call forth responses when 

 applied to the mouth of certain vertebrates or the tentacles or mouth region of 

 certain invertebrates 



1 N.R. signifies that there was no reaction. 



