THE CELL 105 



organisms constituting a volvox colony is quite consider- 

 able; as many as twelve thousand have been counted. 



"It was upon analogous phenomena that Gruber based 

 the existence of a diffused nervous system in the stentors. 

 The same line of reasoning may be followed in the case of 

 the volvox. Since unanimity of movement is demonstra- 

 ble among twelve thousand micro-organisms constituting 

 a colony, it must be inferred that their movement is regu- 

 lated by the action of a diffused nervous system present in 

 the protoplasm. This conclusion is all the more interest- 

 ing from the fact that these volvox are vegetable micro- 

 organisms. In the dioecian volvox the female cellules 

 and male cellules are joined together by themselves in 

 separate colonies. When the time of fecundation arrives 

 the male cellules scatter and proceed to conjugate with 

 the female cellules. The colony which bears the female 

 cellules also contains neutral cellules which are not desig- 

 nated for fecundation ; the latter simply perform a loco- 

 motive function ; equipped with one eye and two flagella, 

 they are intended to move the great colonial ball ; they 

 are the oarsmen of the colony. The volvox male, female 

 and neutral all seek the light, whether solar or artificial, 

 and settle near the surface of the water. As soon as the 

 female colonies have been fecundated, the oospores 

 change their color, they turn from green to an orange 

 yellow. At this time the colony is seen to draw away 

 from the light and to disappear from the surface of the 

 water. This change of position is affected by means of 

 the vibratile cilia with which each neutral cell is furnished 

 and which projects beyond the gelatinous sphere. Now 

 as no change of color or form is noticed in the neutral 

 cells after fecundation, it may be asked from what cause 

 they flee from the light which they formerly sought." 



You notice he ends by asking why they leave the light 



