THE AXIAL ROTATION OF AQUATIC MICRO- 

 ORGANISMS AND ITS SIGNIFICANCE'^- 



Some studies concerning the axial rotation of aquatic 

 microorganisms occupying my attention during the last 

 two years, have yielded results which it is believed are of 

 decided importance in connection with the principles 

 underlying evolution. 



In general it may be stated that the positively photo- 

 tactic free swimming forms of the northern hemisphere 

 rotate clockwise, assuming the observer in front of the 

 advancing organism, and the negatively phototactic forms 

 counter-clockwise, while in the southern hemisphere there 

 are reverse conditions. The apparent exceptions thus far 

 noted have been found closely allied to northern forms 

 and may have been introduced subsequent to the origin of 

 the southern forms. 



The evidence although far from complete is gradually 

 accumulating that the characteristic is one which has been 

 gradually impressed upon the organisms through the rota- 

 tion of the earth and the apparent path of the sun from 

 east to west. Any attempt to account for it on the basis 

 of natural selection can scarcely gain credence. While 

 the possible effects of the angular velocity of the earth or 

 of certain electrical conditions may be considered, it does 

 not seem that the result could in this way be explained. 

 Experimental attempts to reverse or to diminish the rapid- 

 ity of the rotation of the organisms have thus far failed. 



The problem is an interesting one from the geophysical 

 as well as the biological point of view, and many interest- 

 ing principles come under consideration. Among these 

 may be mentioned the Pendulation Theory, Bipolar Dis- 

 tribution, The Twining of Plants, The Tropism Theory, 

 etc. Similarly the direction of the spirals in Spirochaeta, 

 Spirulina, Arthrospira, Spirogyra, etc., are of interest. 



*Reprinted from The Ohio Journal of Science, vol. 18 (1917), pp. 6-7. 



