GRANULATION TISSUE 85 



What I looked for most closely was to see whether the dividing 

 connective-tissue cells assumed appearances like those bodies I had 

 regarded as protozoa in cancerous tissues. This I found not to be 

 the case. 



Nucleoli. In studying the granulation tissue I paid close ^atten- 

 tion to the nucleoli of the connective-tissue cells. Nucleoli were 

 present in many of the cells the nuclei of which were not in mitosis. 



FIG. 29. TYPES OF NUCLEI IN FIBROBLASTS. (From a Biondi-stained section 

 of rabbit's tendon. Camera drawing, x 800 diameters.) 



i and 2, Nuclei with fine reticulum of chromatin, in i there are three nucleoli and 

 in 2 there is one nucleolus. In this case the nucleoli are net-knots or plas- 

 mosomes /'.<?., stained like the chromatic network with which they are 

 continuous ; 3, near the middle of the nucleus is a nucleolus, the outer part of 

 which was stained by the basic stain like the chromatin network, which it 

 joins at several points, and its central part stained with acid dyes ; 4, a nucleus 

 with the chromatic network very little developed, and four oxyphile nucleoli. 



These nucleoli appeared as round or oval bodies, which stained 

 chiefly with the acid dyes when mixed stains were used. 1 



Of all the cell-organs the nucleolus is perhaps the least com- 

 pletely known, but in these connective-tissue cells it appears to have 

 what is its commonest constitution and function, undifferentiated 

 protoplasm, from which chromatin is formed before the mitotic 

 change begins. The most rudimentary forms of some protozoa 

 have a quite similar constitution, and experienced biologists have 



1 As stated above, I have not kept the sections on which my description of the 

 change in rabbits is based, and for the past twelve years I have been without the 

 necessary facilities for pursuing practical work in that direction. I have, however, 

 found one of the sections, which I have restained with Biondi, and from this the 

 cells in Fig. 29 were drawn. 



