98 THE CRITERIA OF LIVINGNESS 



protoplasm between it and freedom. It then broke loose, 

 escaped completely, and was not further molested. If this 

 behaviour had been described and even drawn by a tyro, 

 we might have distrusted it entirely, but when we have it 

 from a master in the difficult art of observing Protozoa, 

 we must give it careful consideration. Without saying any- 

 thing just now about the Amo3ba's mind, must we not agree 

 that this concatenation of following, catching, losing, chasing, 

 re-capturing, and losing again is either behaviour or magic ? 



Most living creatures show more behaviour than is gen- 

 erally supposed, but many of them, plants especially, have 

 little. We often complain that they do not show any inter- 

 esting habits when we are watching them. This may be 

 admitted, however, without affecting the general truth of the 

 statement that organisms are characterised by a capacity for 

 effective behaviour. That many men run their lives, or 

 have to run their lives with a minimum of thinking, does 

 not affect the general truth of the statement that men are 

 characterised by a capacity for rational discourse. 



(&) The effectiveness which characterises the behaviour of 

 those organisms that show enough to be profitable subjects of 

 study, appears to depend on profiting by experience in the in- 

 dividual lifetime, or on the entailed results of ancestral ex- 

 periments (chiefly, perhaps, in the form of germinal varia- 

 tions), or, usually, on both. The registration of experience 

 and experiments is one of .the insignia of organisms, but 

 we must include under the term organism the germ-cell, 

 which is an implicit organism, a microcosm corresponding 

 to the macrocosm which develops from it. We must include 

 the germ-cells because, so far as we can judge at present, 

 many if not most new departures of importance have had 

 their origin as germinal variations. If the word ' experi- 



