STUDIES ON THE PERMEABILITY OF CELLS 



EDMUND NP]\VTOX HARVEY 



From the Zoological Laboratory, Columbia University 



THREE FIGURES 



CONTENTS 



Introduction 50S 



1. Historical 508 



2. Theories concerning permeability 509 



3. Methods of testing permeability 512 



The penetration of aniline dyes 514 



1. Mechanism of staining plant cells 514 



a Overton's hypothesis 514 



b Elodea 515 



c Theory of indicators applied 516 



d Action of the acid is on the dye 516 



e Spirogyra 517 



2. Relation to Overton's lipoid theory 519 



3. Mechanism of staining animal cells 522 



a Paramoecium 522 



b Marine eggs 524 



The penetration of alkalies 525 



1. Method and previous results 525 



2. Objections to the use of an indicator within a cell 527 



3. Experiments with plant cells 530 



a Strongly dissociated alkalies 530 



b Weakly dissociated alkalies 532 



c Permeability of cells exhibiting protoplasmic rotation 536 



d The concentration of alkali which stops rotation 537 



e The effect of added substances on the penetration of NaOH and KOH 538 



4. Experiments with animal cells 541 



a Paramoecium 541 



b Marine eggs 547 



Discussion 551 



Summary of results 554 



Bibliograph}' 556 



507 



