21 2 



AmtlluT liUMn ol' (Icuit'iicralion is llic j^ianl fells, tli',' ffe- 

 nesis ol' wliicli is slill unknown Aircaciy from Ihc very 

 early days ol" lissue cnllivalion L a ni h c r I -"''^i has sludicd 

 llu' I'ornialion ol" Ihe Torciifn Ixjdy <fianl (U'lls in xiiro. lie 

 inlioduced I y e o p o d i n ni spores into eullures ol' s|)leen. 

 lie also observed thai olhei* I'oi'ei.uin bodies, such as collon 

 threads or the coverglass itself initialed the formation of 

 giant cells. I myself*) found in old degenerated euliures 

 of ei)ithelium giant cells with ahoul .')() nuclei. 



There has been much discussion as to the mechanism of 

 the formation of giant cells. The general assum|)tion of the 

 origin of the giant cells is that of the fusion of few' or 

 several large mononuclear wandering cells. The other pos- 

 sibility of origin for the giant cells is that the nucleus 

 divides without division of the cytoplasm. W. 11. Lewis 

 and Webster ^*^-) have observed one clear case w^here 

 the nucleus divided amitotic without any division of the 

 cytoplasm. They also concluded that the giant cells seemed 

 to be formed, for the most part, within the exi)lanl and to 

 misrate out after their formation. 



The origin and formation of the various intercellular 

 substances has been studied by means of tissue cultivation. 

 The hyaline substance of the cartilage, the bone formation, 

 the enamel of the teeth, the fibi'ous fibrilhe of the con- 

 nective tissues and so forth will find an useful method in 

 explantalion. 



INIuch discussed is the origin of the connective tissue 

 fibres. The stud}' of fixed and stained preparations of tis- 

 sues has so far failed to decide the origin of the con- 

 nective tissue fibrilhe. It is still an open question, whether 

 the fi])rilhe arise within the fibroblasts or from an inler- 

 eellular substance. 



*) Fischer, A. Unpublished experiments. 



