152 HAECKEL 



the cell-theory a short time before. He looked 

 upon every individual man as a mysterious plurality 

 — a plurality of cells. Pathology, the science of 

 disease, must take account of this. Health was 

 the harmonious co-operation of the cell-state; 

 disease was the falling-away of some of the cells 

 to special work that injured or destroyed the whole 

 community. This conception had inaugurated a 

 new epoch in medicine, making it a consciously 

 ministering art in the service of the living human 

 natural organism. The Darwinian had now the 

 task of showing the validity of this conception in 

 his own province. The genealogical tree of the 

 animals and plants must at once be drawn up in the 

 form of a genealogical tree of the cell. The cells had 

 combined to form higher and higher communities, 

 and each higher species of animal or plant was in 

 reality one of these social constructions. But this 

 complexity was only found in the upper branches. 

 The lower we descend, the simpler we find 

 organisms. The lowest forms of life represent 

 cruder, simpler, and more primitive cell-structures. 

 And the final conclusion was that all the cell- 

 communities or states must have been evolved 

 from unattached individuals whose whole body 

 consisted of a single cell. We cannot strictly call 

 these lowest forms of life either animals or plants ; 

 they can only be likened to the single cell. 

 Though Haeckel himself did not know it at the 

 time, all his pretty radiolaria at Messina belonged 

 to this category. The whole swarm of bacilli and 

 bacteria fell into this world of the ''unicellulars." 



