98 THE CRITERIA OF LIVINGNESS 



protoplasm between it and freedom. It then broke loose, 

 escaped comj^letely, 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 Amoeba's mind, must we not agTee 

 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. 



(b) 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- 



