CARNOY’S CELL RESEARCHES. A485 
chromatin” of Pfitzner), which encloses in its meshes a 
granular liquid (“ enchylema” of Carnoy, ‘‘ achromatin” of 
Pfitzner). It has, in a word, the optical and chemical pro- 
perties of protoplasm. Carnoy maintains that it is protoplasm ; 
cytoplasm is protoplasm outside the nuclear membrane, caryo- 
plasm is protoplasm shut up within it. 
How is this view justified? First of all by observation. The 
reticular structure of the plasmatic element may be made out by 
direct observation in those nuclei in which, as in Pl. XX VI, 
figs. 1 and 2 here, figs. 96—100, 118 of the ‘ Biologie,’ and many 
others, the chromatic filament is not distributed throughout the 
whole nuclear space, but forms a small central clew, leaving the 
peripheral zones free. This kind of nucleus is somewhat un- 
common, yet not so exceptional but that it is well worth while 
to look for it. Carnoy recommends for this purpose the testicular 
cells of Lithobius forficatus. I have seen this structure 
in the epithelium of the intestine of Musca, but am not sure 
that it can always be found there. It is not an artifact, as I 
have been able to prove by observation of living objects (larvze 
of Syrphida). In such objects as these, and in many ova, if 
not in most, the existence of an achromatic mitome! is as 
directly evident as that of the cytoplasmic mitome. In 
common nuclei it may be made out by careful study of very 
thin sections, and sometimes by dissection (see fig. 2). Diges- 
tion is useful, and so is treatment by solvents of nuclein, such 
as carbonate of potash. And, secondly, this view can be justi- 
fied dialectically. In the karyokinesis of certain nuclei the 
spindle may be observed fully formed in the interior of the 
nucleus whose membrane is still perfectly entire. In these 
nuclei, therefore (and the number of these cases hitherto 
observed is not inconsiderable), we are obliged to admit the 
existence in the nucleus of an achromatic element capable of 
forming the spindle-fibrils. And that this element is proto- 
plasm is proved by its genesis. In every case of normal 
1 Carnoy says “network.” I have preferred to say ‘“‘mitome,” because I 
am personally not satisfied as to the reticular nature of the arrangement of 
the fibrils that I see, 
