Nerve-Conduction in Cassiopea Xamachana. 



11 



as shown in table 3, the temperature of the solutions being 29 C. 

 and the neutral point 6.88 P H . 



TABLE 3. 



The effects are not so marked as those which are observed when the 

 pulsating rings are taken from natural sea-water and placed hi sea- 

 water diluted with slightly acid distilled water, or in sea-water made 

 alkaline by being concentrated by evaporation at ordinary tempera- 

 tures exposed to the air; but they accord with expectation in so far as 

 they go. Possibly the OH' anion is stimulating even after it penetrates 

 the cell membranes, while the hydrogen cation is depressant under these 

 conditions. 



The effects upon the rate of nerve-conduction in Cassiopea which 

 resulted from diluting Tortugas sea-water with alkaline distilled 

 water of P H about 8 and with slightly acid distilled water of P H 

 about 6 are given in table 4, which shows that acid distilled water 



TABLE 4. (Illustrated by figure 8.) 



is slightly stimulating in comparison with alkaline distilled water in 

 weak dilution down to about 75 per cent sea- water plus 25 per cent 

 distilled water, and then becomes relatively depressant in stronger 

 dilutions. There are many examples of this in the author's past 

 experiments published in 1914, 1915, and 1916, wherein the distilled 

 water used for dilution was usually acid. An interesting parallel 



