180 W. C. ALLEE 



neutralize the effect of the anion. As to which of these possi- 

 bihties is correct my work offers no direct proof. 



The depressing effect of acids on nervous tissue is well known 

 to physiologists (Mathews '04). They antagonize sodium 

 chloride (Osterhaut '14) but less than calcium chloride and they 

 depress permeabiUty as also does calcium. The effect on rheo- 

 taxis is in accord with this work but with it opposes the ob- 

 servations of Bohn ('12) that N/1000 sulphuric acid increases 

 the oxidation rate of lobster larvae and thereby causes them 

 to become positive to light, and those of Lillie ('09) that N/400 

 and weaker solutions of hydrochloric acid increase permeabiUty 

 and stimulate Arenicola larvae. 



Alkalies {OH ions) 



Mathews ('04) found that hydroxyl ions are most efficient 

 nerve stimulants. Bohn ('12) found that lobster larvae were 

 made positive to light by N/1000 sodium hydroxide and states 

 that the action is similar to that of sulphuric acid but less rapid. 

 Loeb and Wasteneys ('13 a) report that sodium hydroxide has 

 no effect on the rate of oxidations of fertilized Strongylocentrotus 

 eggs unless the concentration is above N/1000 and ('15) that 

 this minimal concentration varies with different species. More 

 concentrated solutions cause a marked increase in the oxygen 

 consumption but the eggs are injured. Osterhaut ('14) found 

 that in the above strength sodium hydroxide makes practically 

 no change in the permeability of Laminaria. Kanda, ('14) 

 using N/20 potassium and sodium hydroxides obtained no 

 reversals in geotaxis with Arenicola larvae although in common 

 with Bohn and earlier workers he did obtain reversals in the 

 reaction to light. Lillie ('09) using N/25-N/100 sodium hy- 

 droxide found no stimulation of Arenicola larvae and suggests 

 that it decreases permeability. 



Potassium and sodium hydroxides were tested for their effect 

 on rheotaxis, the former in N/50 and N/200 solutions and the 

 latter in N/200 and N/500. With the weaker solution of potas- 

 sium hydroxide two of six isopods were slightly stimulated and 



