Structure and Polarity of Electric Motor Nerve-Cell in Torpedoes. 229 



the largest of them are far smaller than the smallest karyosomes. Like 

 the karyosomes they take basic dyes and in the best sublimate fixations 

 they also stain black with iron hematoxylin. These perichromosomes 

 were not differentiated by Magini from the general mass of perichro- 

 matin of the spherule. 



The perichromosomes are much smaller and more numerous than 

 any of the karyosomes; it may be said that they form a group of gran- 

 ules grading down from the less numerous larger ones to finer and 

 more numerous, until the successive sizes become so small that they 

 can no longer be seen. Hence, it is possible that the visible perichromo- 

 somes are not different in substance from the mass of perichromatin 

 in which they lie. They appear in most cases to stain in much the 

 same way as the cloud of finer perichromatin in general, and this 

 perichromatin usually stains differently from the karyosome in its 

 midst. The larger perichromosomes are faintly visible in the fresh 

 state. They seem quite a different substance than the karyosomes. 



Taken as a mass, each karyosome, together with its spherical sur- 

 rounding framework of linin in which are dissolved or borne as fine 

 granules the perichromatin and perichromosomes, forms a unit which 

 is, as has been said, of about the size of a full-sized single plasmosome. 

 It will be convenient and perhaps permissible to call these complete 

 units the " chromatin bodies." It is possible that they are the same as 

 the chromosomes of dividing cells. 



It may thus be seen that in the adult electric motor nerve-cells of the 

 torpedoes in general there are at least six apparently separate materials 

 which are not dissolved by the usual fixatives by subsequent handling 

 with reagents, and which can be recognized and compared by their 

 size, shape and staining capacity as well as, in some cases, by their 

 specific gravity and their refractive index. 



I regard these substances as organic compounds that take part in 

 the life and activity of the nucleus and therefore of the cell, but some 

 of which, at the time the cell is fixed in a more or less solid state, are 

 possibly in a state of storage or temporary disuse. The reason for 

 their solid form is a question of segregation of the particular material 

 involved. This does not imply that the material in question is not 

 active, for it probably is, but it does seem that it is necessary, for 

 physiological-chemical purposes, that it be more or less concentrated 

 at some particular point. Nor is its solidity an absolute one, but 

 consists of varying degrees of gelatinization or even of strong solution, 

 which are usually much intensified by the fixation, etc. Many other 

 constituent substances of the nucleus must be in the form of solutions 

 that are not precipitated by our fixatives and are consequently not 

 ordinarily studied. Some of the latter substances are sometimes pre- 

 cipitated and preserved for study, and sometimes they remain in solu- 

 ble form or are even converted from solid and gel forms to a solution 



