28 CALIFORNIA ACADEMY OF SCIENCES. [ 3 d Ser, 



by themselves. This unity must ultimately be ascribed to 

 difference in structure, quality, and organization of the pro- 

 toplasm, entitling it to be considered separately. For the 

 protoplasm of the microcentral spheres I therefore propose 

 the word archosomo-plasm, giving it equal value and im- 

 portance with the cytoplasm of the cell and of the cary- 

 oplasm of the nucleus. While we may use these words for 

 convenience sake, we may neither imply that the archo- 

 somoplasm, caryoplasm, and cytoplasm are not further sep- 

 arable into distinct kinds, nor that parts of cytoplasm, for 

 instance, may not at times be found mixed with caryoplasm. 

 How many distinct kinds of caryoplasm and archosomoplasm 

 there really are will probably not soon be definitely decided, 

 but I think we can safely argue that every part of protoplasm 

 which differentiates in staining constitutes a kind of its own, 

 differing in quality and function from the rest. That the 

 centrosphere and somosphere do not always differentiate 

 in the same manner does not prove that they are not always 

 equally distinct from each other. Too long exposure to the 

 stain will always destroy the differentiation, while at times 

 permeation with food granules and liquids will greatly lessen 

 or affect their susceptibility. 



X. Development of the Plasmocytoblast into Plas- 



MOCYTES. 



I have already pointed out that by arranging and compar- 

 ing a series of drawings of plasmocytoblasts it soon 

 becomes evident that they are respectively in different 

 stages of development; not only are some of them much 

 larger than others, but the larger ones show a differen- 

 tiation not found in the others. If we study such of the 

 figures as 28, 33$, 37, etc., we observe that the inner spheres 

 have divided, a division apparently caused by a separation 

 of the centrosomes, which latter have carried with them, 

 each one separately, an envelope of one or two spheres. 

 Thus in fig. 35a the white somosphere is dividing and 

 in each division is found a centrosome: in fig. 33 each 



