19 



particle of protoplasm suspended in a fluid would, just as an 

 oil-drop does, tend to assume a spherical form, on the prin- 

 ciple of Plateau's Avell-known experiments. But this would 

 not account for the definite elongate shape of a bacterium 



Fig. 1. X 2S00. 



Pig. 2. x 2800. 



(Figs. 1 and 2), the difference between which and the 

 rounded outline of a monad or Torula germ must depend on 

 difference in their component organic units. ^ These may be 

 comparatively simple, though not necessarily so, since bacteria 

 may be stages of more complex organisms, capable of attaining 

 complete development in a more favorable environment. 



If there is little analogy between the supposed origination 

 of such entities as bacteria and crystallization, still less is 

 there in the case of spores of fungi. The existence of a 

 spore or germ implies the development of something more 

 mature, the form of which is implicitly determined by it. Its 

 component organic units must, therefore, be more complex 

 than those of the simplest living bodies which run through 

 no varied course of development. A germ apparently ex- 

 tremely simple in structure potentially may be rather complex, 

 and in proportion its production by mere segregation from a 

 solution of colloidal matter is a priori improbable. There is 

 good reason for believing that even when " under tbe influence 

 of pre-existing protoplasm an equivalent weight of the matter 

 of life makes its appearance " in the place of carbon dioxide, 

 water, and ammonia, it does so only after a process of evolu- 

 tion by successive integrations. It is alien to the general 

 conception which evolution forms of the mode in which the 

 more complex kinds of matter are derived from the less complex 



^ These figures, wliicli are perhaps the most definite that have beeu pub- 

 lished, are borrowed from Br. Beaie, 'Disease Germs,' PI. II, fig. 13, and 

 PI. IV, fig. 26. Pig. 2 represents l)acteria with white and red blood-cor- 

 puscles from hepatic vein of a cow which died of cattle plague. 



