186 THE INDUCTIONS OF BIOLOGY. 



unit life. Nor, indeed, are we shown this only in the lowest 

 plants; for it has recently been found that in certain of the 

 higher plants — even in Phaenogams — spermatozoids are pro- 

 duced. That is to say, the units resume active lives at 

 places where the controlling influence of the aggregate is 

 failing; for, as we shall hereafter see, places at which gene- 

 ration commences answer to this description. 



These different kinds of evidence jointly imply that the 

 individual lives of the units are subordinate to the general 

 life in proportion as this is high. Where the organism is 

 very inferior in type the unit-life remains permanently con- 

 spicuous. In some superior types there is a display of unit- 

 life during embryonic stages in which the co-ordinating 

 action of the aggregate is but incipient. With the advance 

 of development the unit-life diminishes; but still, in plants, 

 recommences where the disintegrating process which initiates 

 generation shows the coercive power of the organization to 

 have become small. 



Even in the highest types, however, and even when they 

 are fully developed, unit-life does not wholly disappear : it is 

 clearly shown in ourselves. I do not refer simply to the 

 fact that, as throughout the animal kingdom at large and a 

 considerable part of the vegetal kingdom, the male gene- 

 rative elements are units which have resumed the primitive 

 independent life, but I refer to a much more general fact. 

 In that part of the organism which, being fundamentally 

 an aqueous medium, is in so far like the aqueous medium in 

 which ordinary protozoon life is carried on, we find an essen- 

 tially protozoon life. I refer of course to the blood. Whether 

 the tendency of the red corpuscles (which are originally 

 developed from amoeba-like cells) to aggregate into rouleaux 

 is to be taken as showing life in them, may be left an open 

 question. It suffices that the white corpuscles or leucocytes, 

 retaining the primitive amceboid character, exhibit indi- 

 vidual activities: send out prolongations like pseudopodia, 

 take in organic particles as food, and are independently loco- 



