256 The Unity of the Organism 



that it may remain intact after the softer, more plastic parts 

 of the body have undergone dissolution. It reminds one of a 

 skeleton quite as much as of any other system belonging to the 

 higher animals, though this remark is not intended as a sug- 

 gestion that it may be of this nature. But the fact of capital 

 importance to the present discussion is the remarkable degree 

 of structural unification, or in accordance with the terminology 

 favored by us, the structural integratedness of the animal through 

 this organ system. All analogy warrants the supposition that 

 functional integration of some sort corresponds to this structural 

 integration, and if ever research discovers what that function 

 is (or those functions are, for the possibility that there may 

 be several should never be lost sight of), the insight thus 

 obtained into the nature of these creatures would be another 

 long step toward banishing the doctrine of the simplicity of 

 the protozoa. 



The Fiction of Structureless Organisms 



Having informed ourselves concerning the highest grades 

 of organization known among unicellular beings we must 

 inquire about the lowest grades. The immediate question is, 

 are genuinely structureless or homogeneous or amorphous 

 living beings known .^ The next and far more searching 

 question is, if such beings are not known (and they surely 

 are not) does the nature of the inductive evidence demand 

 or even warrant the supposition that tliey must exist some- 

 where or must have existed at some time although we can 

 get no evidence to this effect.'^ 



The supposed existence of beings of this sort has cut a 

 large figure in speculative biology. One need only refer to 

 the moneron theory of Haeckel and its wonderful vitality 

 shown by its cropping out everywhere, even in elementary 

 and popular writings, and by its receiving a show of assent 

 simultaneously with the admission that actual observation 

 tends to disprove the theory. A good example of the per- 

 sistence of the teaching is shown by Haeckel's The Evolution 

 of Man. In the fifth edition, English, 1903, we read, "The 



