No. 589] THE EVOLUTION OF THE CELL 27 



only with living things as he knows them, Haeckel's 

 plasson must rank as a pure figment of the imagination, 

 altogether outside the range of practical and objective 

 biology at the present time. All visible living things 

 known and studied up to the present consist of proto- 

 plasm, that is to say, of an extremely heterogeneous sub- 

 stance of complex structure, and no living organism has 

 been discovered as yet which consists of homogeneous 

 structureless albuminous substance. Van Beneden, who 

 is responsible for the word plasson, though not for the 

 cytode-theory, was under the impression that he had ob- 

 served a non-nucleated homogeneous cytode-stage in the 

 development of the gregarine of the lobster, Gregarina 

 (Porospora) gigantea. Without entering into a detailed 

 criticism of Van Beneden 's observations upon this form, 

 it is sufficient to state that the development of gregarines 

 is now well known in all its details, and that in all phases 

 of their life-cycle these organisms show the complete 

 cell-structure, and are composed of nucleus and cyto- 

 plasm. Moreover, all those organisms referred by Haeckel 

 to the group Monera which have been recognized and 

 examined by later investigators have been found to con- 

 sist of ordinary cytoplasm containing nuclei or nuclear 

 substance (chromatin). In the present state of biological 

 knowledge, therefore, the Monera as defined by Haeckel 

 must be rejected and struck out of the systematic roll as 

 a non-existent and fictitious class of organisms. 



Since no concrete foundation can be found for the view 

 that cytoplasm and chromatin have a common origin in 

 the evolution of living things, we are brought back to the 

 view that one of them must have preceded the other in 

 phylogeny. The theories of evolution put forward by 

 Haeckel and his contemporaries, if we abolish from them 

 the notion of plasson and substitute for it that of ordi- 

 nary protoplasm, would seem to favor rather the view 

 that the earliest forms of life were composed of a sub- 

 stance of the nature rather of cytoplasm, and that the 

 nuclear substance or chromatin appeared later in evolu- 



