VOLITION AMONGST THE BRUTES 159 



But, it will be said, the behaviour of the lower 

 animals is regulated by directive instinct : what 

 scope can be left to them for spontaneous action ? 

 Their behaviour, indeed, approaches the mechani- 

 cal. But it does not exactly resemble clock- 

 work or the movements of iron filings in the 

 presence of a magnet. In the lower ranges of the 

 animal kingdom the promptings of instinct are 

 very peremptory and extraordinarily detailed. 

 But cases arise for which they do not provide, 

 and we may see ants, bees, and spiders hesitate 

 and make trials when confronted with unusual 

 difficulties. In fact the directions of instinct do 

 not cover the whole of the ground, and leave 

 some opportunities for the making of mistakes 

 and of attempts to rectify them. The behaviour 

 of insects is occasionally guided by trial and rejec- 

 tion, and in this differs altogether from the action 

 of machinery. You may see a line of ants checked 

 and apparently perturbed by an unusual obstacle : 

 one of them finds a way to circumvent it, and the 

 rest follow its spontaneous lead. Bees will vary 

 the shape of their cells in order to carry their 

 combs round an obstruction. Higher up the 

 scale, as the promptings of instinct become less 

 and less elaborate, the scope for experiment 

 for making choices widens : we have already 

 seen that birds, for instance, will on occasion 

 depart very considerably from their instinctive 

 procedure. In man the field for spontaneous 

 action is incomparably wider than in any of the 

 animals below him. But the field extends through- 

 out the province of Life, narrow though it be 

 when we reach its humblest regions. There is a 

 period in the life of each plant when certain of 

 its cells appear to be confronted with a choice. 

 And the lively activity that is displayed by the 

 minute unicellular organisms which flit across the 



