78 MONTROSE T. BURROWS 



never showed activity except in a few cases of the latter type. 

 Growth took place at the few points where the fibrin was in contact 

 with the tissue. The nerve fibres are also dependent on such 

 support for their growth, as Harrison has pointed out. 



Many of the star-shaped and the irregularly shaped wandering 

 cells show a constant slow alteration in their outline, while in the 

 case of the spindle cells the long pointed spindle-form is not changed 

 often during a passage of several millimeters. The only evidence 

 of movement in these cells, aside from their change in position, 

 is the rearrangement of the granules in long rows in the end proc- 

 esses. In the cases where the cells find attachment along the side 

 of a coarse horizontal band of fibrin, a movement of the outer 

 layer of the protoplasm about the axis might account for the ar- 

 rangement of the granules and the progress forward, with the 

 maintainance of the cellular tension. 



Such growing cells from an isolated piece of tissue have at no 

 time shown evidence of grouping in a form comparable to organ 

 formation in the body. Their growth and morphology, as studied 

 by a careful comparison of the preparations, seem to be governed 

 by the varied chemical and physical relations of the medium in 

 which they are grown. To complete the discussion of these cells, 

 some of the different morphological type will be considered with 

 their relation to the architecture of the clot. 



The spindle cells 



These cells grow commonly from the points of the tissue from 

 which radiate long coarse fibrin bands (fig. 12). They appear as 

 single slowly moving spindle-shaped cells, closely adherent to the 

 side of this coarse fibrin band. Aside from the inability to observe 

 active contractions of this fibrin band, one might conclude that 

 they had been pulled out of the tissue by some outward force. In 

 the so-called ring formations observed by Harrison, spindle cells 

 are formed from preexisting oval or polygonal-shaped cells by a 

 visible active change of the clot. The formation of the ring-like 

 openings occur in the clot after a few days of incubation by a 

 breaking of the continuity of the net at a point, associated with 



