3 2o Phillips on a Comparative Study of the 



which they retain but a short time, finally reacting to all 

 tests in the same manner as the cell wall of the older 

 portions of the Cyanophyceas, with which they become 

 continuous. 



What the function of these hairs is, I have not been able 

 fully to determine. That they are not parasitic growths, 

 however, but living portions of the Oscillaria filaments 

 which have grown out from the cell protoplasm, either 

 through pores specially digested out of the free cell wall 

 by means of a ferment, or more likely through the pores 

 formerly occupied by the protoplasmic communications 

 between the cells (Fig. 35), there can be no doubt. That 

 they act more or less as a tactile organ, assisting the trich- 

 ome to overcome and get around obstacles met with in the 

 forward progress of the filament, was evidenced many times 

 in the progress of my observations, for I was able to see 

 them swaying from side to side, with a slow but steady 

 independent motion as the Oscillaria filaments moved for- 

 ward or oscillated. They would apparently reach out on 

 one side as if to attach their free ends to something, and 

 then gradually sway over until they became bent in the 

 opposite direction. If the trichome pressed forward against 

 some other object or Oscillaria trichome, these hair-like 

 appendages would, through the activities just mentioned, 

 apparently determine the way to get around the obstacle, 

 as if they were tactile organs that piloted the trichome and 

 assisted it in surmounting obstacles. These actions were so 

 general and constant that, though I do not consider them 

 to be rapid enough to cause the oscillation or creeping move- 

 ments, nevertheless, they were such as to convince me that 

 I was dealing with a definite plant organ. Having deter- 

 mined this, I sought after an adequate cause for the move- 

 ments observed. As has been said above, nowhere in the 

 whole vegetable kingdom, do such movements, the cause of 

 which is understood, occur without ciliary or pseudopodial 

 appendages. Various stains and micro-chemical tests were 



