510 Dr. Andrew Wilson [Feb. 4, 



leads us firstly to define an " individual " structurally as a being 

 whose parts and organs are so closely and intimately connected, that 

 separation of even a limited structural area means disintegration 

 of the individual as a whole. Physiologically, an " individual " 

 animal or plant is the total development of a single egg or seed. As 

 the whole zoophyte, sea mat, and tapeworm arise, each from a single 

 egg, each, in toto, is an " individual." The separate units of each are 

 named " zooids." A new personality does not enter into the life 

 cycle of any animal or plant, until a new egg or seed has been pro- 

 duced. Even in the case of the Hydra, although the buds become 

 detached and to all appearances are each as truly an " individual " 

 as their parent, they possess nevertheless no true personality. 

 They are merely units or zooids of a colony ; they were produced 

 by budding, and as such are not "individuals" but parts of an 

 *' individual." If we assumed that the buds of a zoophyte or tape- 

 worm were " individuals," we might with equal correctness speak of 

 the joints of a lobster or worm as " individuals" likewise. Even in 

 human structure itself, there are to be seen traces of a fundamentally 

 " colonial " nature. The tissues of the highest animals are but 

 aggregations of cells. As such, they have a semi-independent con- 

 stitution ; and there are certain protoplasmic cells (e. g. the white 

 or amoeboid corpuscles of the blood) which roam independently at 

 will through the body, and possess powers of movement exactly 

 resembling those of the Amoeba and its kind. 



A progressive tendency according to the theory of evolution marks 

 the organic series. The conversion of the " colony " into the " in- 

 dividual," in other words the concentration of originally separate 

 and independent "units" or "zooids," is the chief developmental 

 cause of the differences between high and low organisms. The 

 primitive condition of all organisms is the " colonial " condition. 

 Egg-segmentation (or in Protozoa body-division) is universal in the 

 animal world; and cell-multiplication begins the development of 

 plant life likewise. Arrest of development at an early stage dis- 

 tributes the separate units thus formed (as in Gregarina) ; arrest at a 

 later stage gives us the sponge colony (a series of similar aggregated 

 cells), or the tapeworm colony (a collection of essentially similar 

 "joints"). Physiologically, the higher organism devotes less time to 

 pure reproduction and becomes more explicitly busied with individual 

 interests. Hence the increased concentration of energy which results 

 in the formation of the highest " individuals," that yet retain, in the 

 " colonial " and cellular structure of their tissues, the evidence of an 

 originally compound nature. 



In the plant world, such " individualization " is seen as a 

 secondary tendency in the close aggregation of flowers in Compositce, 

 and in the transformation of uniform composites (e. g. thistle) into 

 individualized forms (e. g. daisy) through such intermediate steps as 

 the centauries. 



The conclusions of our study of "colonial" organisms are as 



