Vol. XXXVI. March, 1919. No. 3. 



BIOLOGICAL BULLETIN 



ON THE REVERSIBILITY OF THE HELIOTROPISM 

 OF ARENICOLA LARV^ BY CHEMICALS. 1 



SAKYO KANDA, 



THE PHYSIOLOGICAL LABORATORY, KYUSHU IMPERIAL UNIVERSITY, 



FUKUOKA, JAPAN. 



CONTENTS. 

 I. Introductory 149 



II. Material and Methods 150 



III. Experimental 151 



1. Effects of Temperature Changes 151 



2. Effects of Hypertonic and Hypotonic Sea-water 152 



3. Effects of Isotonic Salt Solutions 153 



4. Effects of Artificial Sea-water 155 



5. Effects of Hypertonic Sodium and Potassium Chloride Solutions 



added to the Artificial Sea-water 156 



6. Effects of Elimination of Salts in the Artificial Sea-water 156 



7. Effects of Alcohols 158 



8. Effect of Saponin 160 



9. Effects of Fatty Acids 160 



10. "Antagonism" between Acid and Narcotics 162 



it. Effect of Butyric Acid in Solution with Artificial Sea-water 162 



12. Effects of Inorganic Acids 162 



13. Effects of Strong and Weak Bases 163 



14. Effects of Chemicals after Returning into Normal Sea-water 164 



IV. Summary 165 



I. INTRODUCTORY. 



Loeb discovered in 1893 that the normal heliotropism of 

 Polygordius larvae and marine copepods could be reversed by 

 changes of the temperature and of the concentration of sea- 

 water. 2 He also found in 1904 that fresh-water crustaceans which 

 were naturally negative or indifferent to light could be made 



1 From the Marine Biological Laboratory, Woods Hole, Mass., and the Phys- 

 iological Laboratory, University of Minnesota, Minneapolis. 



2 Loeb, Jacques, Pfluger's Arch., Bd. 53, p. 81, 1893. 



149 



