644 SCIENCE PROGRESS 



his accounts for some of the difference. But still there is a 

 certain proportion of cytoplasm in the sperm and that has 

 nothing to do except combine with the cytoplasm of the ovum. 

 With this cytoplasm go chondriosomes which fuse with the 

 chondriosomes of the ovum. 1 



Again, in many cells, the nucleus is so small in comparison 

 with the cytoplasm that it long escaped the notice of the micro- 

 scopist. So much so that we still read in histological descrip- 

 tions of a structure being "cellular" in contrast with adjacent 

 living structures and this in spite of the fact that all the 

 structures described are composed of cells and nothing but cells, 

 though the nuclei may be so small as to escape any but the 

 most careful examination. The relative bulk of nucleus to 

 cytoplasm would appear to be determined in each case by 

 adaptation to the immediate environment of the cell. 



I am quite unable to accept the idea that the nucleus alone 

 produces enzymes. Digestion of particles that have been en- 

 gulfed always takes place in the cytoplasm and as I shall 

 describe shortly, there seems to be at times a special provision 

 against the cytoplasm having a chance of acting directly upon 

 the nucleus. All the phenomena that have been described as 

 taking place within the cell as connected with the production 

 of enzymes occur in the cytoplasm and the granules which are 

 connected with these secretions are stated to be derived from 

 the chondriosomes, which in turn have been derived from the 

 chondriosomes of the gametes. 



It is claimed that some organisms, particularly certain 

 bacteria, consist of nucleus only without cytoplasm. This I feel 

 is a somewhat dangerous claim. Cytoplasm has been de- 

 monstrated in many bacteria and when the methods of 

 preserving and staining bacteria become more refined, it seems 

 eminently probable that a thin layer, at least, will be found in 

 all. It is, after all, only a few years ago that parasitic protozoa 

 were always fixed by drying them upon a glass slide, generally 

 by means of violent heat. When the extraordinarily delicate 

 structure of these organisms is considered, it seems wonderful 

 that so much was discovered in spite of this barbarous method. 

 Bacteria are more resistent to rough treatment than are 

 protozoa but still it is too soon to make such a definite state- 

 ment as that some of them have no cytoplasm. Besides this, 



1 Meves, F., 191 1, op. cit. 



