Vitaliti) and Organization of Protoplasm. 25 



and ontogenetic evolution of a vital being, such as the assumed vital 

 units are held to be, is really brought about. And this means here, that 

 the entire problem under consideration has been relegated -wholly un- 

 solved to fanciful realms peopled by imaginary beings. 



Nor, it must be confessed, is it in the least intelligible how bioj)hores, 

 however specifically developed, and emitted from determinants at the 

 right time and in the right place, start suddenly into activity, trans- 

 forming thereby indifferent soma-plasm or morpho-plasm into spe- 

 cifically constituted and specifically functioning tissues. As they do not 

 tliemselves consist of, for instance, muscle or nerve substance, how 

 can they by their mere presence and self-multiplication determine the 

 formation of muscles or nerves, or of any other kind of tissue? Or- 

 ganic tissues can in this theory consist only of aggregations of self- 

 multiplied biophores, which are able to determine or reproduce nothing 

 but their own likeness. 



It is obvious, that in tliis theory also, as in all other aggregational 

 theories, the cell-theory by which it is guided in its exposition, becomes 

 in the course of its application disintegrated. The cell, as a self-divid- 

 ing autonomous being, has dissolved into a multiplicity of other autono- 

 mous self-dividing beings, and is no more itself. 



Finally, it has become extremely doubtful, if not wholly disproved, 

 that it is really a nuclear plasm, which may rightly be called germ- 

 plasm, the plasm that actually undergoes ontogenetic evolution, repro- 

 ducing thereby the adult organism? 



It will be admitted that the fundamental assumptions of a theory, 

 to be really serviceable, must be self-consistent, and must not logically 

 lead to impossible interpretations of actual phenomena. 



SUMMAKY. 



It has been shown, that, under the supposition that the germ-plasm 

 destined to reproduce a complex organism is composed of elementary 

 units ; that under this aggregational view the leading theories of heredity 

 and reproduction are untenable. Yet, assuming, as they mostly do, 

 that higher organisms are really multicelhilar beings, composed of gen- 

 erations of autonomous cells, which are the lineal offspring of a mother- 

 cell, itself an autonomous elementary organism ; taking, in fact, the 

 cell-theory as a safe foundation upon which to rear a theory of heredity 

 and reproduction, they can hardly arrive at different conclusions. It 

 seems, indeed, the only way to account for an elementary self-dividing 

 being having come in the course of phyletic evolution to contain poten- 

 tially the germinal differentiations, which under succes,sive divisions give 

 rise to so divers a progeny as constitute the sundry tissues of higher or- 

 ganisms. 



A cell, being by definition an elementary organism, can legitimately 

 reproduce by means of self-division only its own likeness. But here 

 it is found to reproduce successively differentiated generations of off- 

 spring mostly more highly developed than it is itself supposed to be. 



