118 THE LESSON OF EVOLUTION 



small grains, some larger ones; but, whichever it 

 may be, they are nearly uniform in size with them- 

 selves. This surely is a mental action. 



In Euglaena, belonging to the Flagellata, we also 

 see voluntary movements which are evidently 

 mental in origin. But at certain intervals the 

 animal ceases to move, surrounds itself with a cell- 

 wall of cellulose, and becomes practically a plant. 

 Now, if in its motile condition it had mind, w r e 

 cannot refuse to believe that it contains mind in its 

 resting condition also. Neither can we consis- 

 tently deny mind to plants ; for many of the lower 

 forms have resting and motile stages. Indeed, 

 several of the higher plants are generally allowed to 

 possess sense organs. And if the antherozoid seeks 

 the oosphere by a mental act , so also must the growth 

 of the pollen-tube be a mental act. That it may be 

 deceived by a solution of sugar and water, imitating 

 the secretion of the stigma, is no evidence at all 

 that the action is due to chemical or physical 

 agencies. Another good example of physiological 

 processes being started by artificial physical stimuli 

 is the fact that in the ova of some animals the cen- 

 trosomes can be produced, and development com- 

 menced, by the action of re-agents, such as mag- 

 nesium chloride. But here again the chemical 

 re-agent cannot form the centrosomes. The 

 materials must be there, and the stimulus merely 

 starts them into action, whether it be the natural 

 stimulus of fertilisation or an artificial one. The 

 protoplasm of the ovum, on being stimulated, sets 

 to work in the only way it knows ; that is by pre- 



