Zool.— Vol. I.] EISEX—PLASMOCYTES. 45 



XII. The Independence of the Archosome. 



From the foregoing observations it will be seen, at least 

 in the fusiform elements of the blood, that the archo- 

 some shows an independent life history — surviving, grow- 

 ing, and changing long after the other constituents of the 

 cell have disintegrated As far as I can see the plasmocyte 

 occupies a position equal to that of a real cell. It has all 

 the general qualities of the cell as understood by modern 

 cytologists, with perhaps one exception — the power to re- 

 produce itself; at least no instance of unqualified plasmocytic 

 division has come under my observation. The question now 

 arises as to the relationship which the archosome bears to 

 the nucleus and the balance of the cell. As is well known, 

 there are two opposite views on this matter: one which con- 

 siders the centrosome a constituent of the cell, always pres- 

 ent and of paramount importance in directing the mitosis; 

 the other claiming that the centrosome is only an organ in 

 the cell (like the heart in the animal body), either always 

 present or temporarily differentiated at the time of mitosis — 

 a larger microsome, whatever that may mean, but nothing 

 more. According to the latter theory the only function of 

 the centrosome would be to mechanically direct and carry 

 out the complicated stages of the mitosis, and when this was 

 accomplished its work would be ended.. This theory suf- 

 ficed as long as centrosomes were not found in cells which 

 had lost the power of division, or which would never again 

 divide by caryokinesis; but we now know that centrosomes 

 and archoplasm occur in cells in which cell division will 

 never be repeated. It is not my intention to enter upon this 

 subject extensively at present. However, I will here point 

 out that if we concede that the microcentrum, or archo- 

 some, is always present in every cell, and can recognize 

 that the archosomes in some cells, as for instance in the 

 fusiform corpuscles of Batrachoseps, survive all other parts; 

 that they clothe themselves with various envelopes of cyto- 

 plasmic spheres; that they increase in size and assimilate 

 food; that they remain entirely independent of former asso- 



