4 THE BOOK OF NATURE STUDY 



To illustrate growth without marked change, it is useful to have 

 a series showing different stages, e.g. of a common shell or of the 

 adolescent shore-crab.] 



Another characteristic of living creatures of all sorts and 

 sizes is their power of effective response. The barrel of gunpowder 

 responds to a spark, but it responds self -destructively. The 

 living creature's response is usually self-preservative or, in any 

 case, in the direction of self-preservation. It may not be always 

 successful in its answer, especially when it gets into unwonted 

 conditions, but it is characteristically effective. It may be 

 killed by a flash of lightning to that no answer is possible, but 

 in the ordinary course of its life it is always giving answers which 

 make for continuance or betterment. Moreover, it does not 

 merely react to outside stimulus, it acts. It does things in a sense 

 which cannot be said of a lifeless object. [Throw a piece of 

 potassium on a basin of water, and show it rushing about, fizzing 

 and flaring until it goes out. Contrast this with the movements 

 of a whirligig beetle (Gyrinus natator}, which does not " go out " 

 for a long time. Its activity is rich in effective responses. Show 

 the effective responses in some plants, e.g. the tendril coiling 

 round a support, or the stigma of Mimulus closing on the 

 pollen.] 



Without going further into the subject, we may sum up by 

 saying that living creatures have the power of growing, of cyclical 

 development, and of giving effective responses. But these 

 characteristics may be brought together under the general idea 

 that living creatures are like ourselves in having, each according 

 to its measure, a persistent unified activity, which, in its higher 

 reaches at least, is worthy of being called behaviour. So we come 

 back to what the young child would most naturally say : that 

 living things differ from not-living things in being like ourselves. 

 ilustrate with reference to the behaviour of common animals, 

 and show that the same sort of thing is seen, within limits, in 

 plants, e.g. in their movements. It need hardly be said that there 

 should be no mention in class work of such technical phrases as 

 " cyclical development " and " effective response," and that the 

 three characteristics should be suggested merely by questioning 

 the pupils after showing significant contrasts, such as the growing 



