MOTOR RESPONSES 339 



centration. If it varies indirectly with the amount of salt that enters and 

 this varies either directly or indirectly with the hydrogen ion concentra- 

 tion practically none of the results obtained are in accord with the assump- 

 tions. If it varies directly with the amount of salt that enters and this varies 

 directly with the hydrogen ion concentration the results obtained with 

 balanced salt solutions and some others are in full accord with the assump- 

 tions; but the assumption that the entrance of salts varies directly with 

 hydrogen ion concentration is not in harmony with the results obtained by 

 practically all who have investigated this problem. Moreover, the assump- 

 tions do not account for the independence or inverse variation between hydro- 

 gen ion concentration and gel/sol ratio in calcium solutions. . . . 



If they are in accord with the second of the three assumptions made above, 

 the gel/sol ratio must depend upon the hydrogen ion concentration with- 

 in the cell and this must vary with the concentration of the salts and the 

 hydrogen ions in the surrounding medium. If it varies indirectly with the 

 hydrogen ion concentration of the surrounding medium and directly or 

 indirectly with the salt concentration, few if any of the results obtained 

 are in accord with the assumptions. If it varies directly with the hydrogen 

 ion concentration and the salt concentration of the surrounding medium, 

 the results obtained with balanced salt solutions and some others are in ac- 

 cord with the assumptions, but those obtained with calcium solutions are 

 not. There is, moreover, no evidence which indicates that the hydrogen ion 

 concentration within Amoeba varies appreciably with variation in the hydro- 

 gen ion and the salt concentrations of the surrounding medium (Chambers, 

 1928). ... 



In accord with the third group of assumptions, the gel/sol ratio must vary 

 with the rate of exit of substances from the cell, and this must vary di- 

 rectly or indirectly with the salt and the hydrogen ion concentration, and it 

 must also vary with the kind of salts present in the environment. Without 

 entering upon a detailed analysis of the correlation between these assump- 

 tions and the results under consideration, it is evident that, no matter what 

 combination is selected, there are between them and the results inconsist- 

 encies of the same nature as those presented above. . . . 



It is consequently obvious that the results in hand cannot be consistently 

 explained by any one of the three groups of assumptions made, and that 

 there must be a fairly complicated interaction between the various factors 

 involved. If this is true, the statement, without qualification, that any given 

 factor facilitates gelation or solation is obviously so incomplete that it is 

 without value. This conclusion is in full harmony with that reached by 

 Mast and Prosser (1932). . . . 



In reference to the relations between rate of locomotion and kind of 

 salts, salt concentration and hydrogen ion concentration, the results ob- 

 tained are, on the basis of any one of the groups of assumptions considered 



