212 THE MOSAIC STAGE OF DIFFERENTIATION 



■W^ - ' - . "— .^ - "' ^'"^ — msl.fbr. 





^ 



'/-- 



msl.fbr. 



^=-fbl.lyr, 



■ — deg. ov. 



i-':.-: % 



t) f > 



_ — msl.fbr. 

 — -msl. nuc, 



>fbl.lyr. 



— cil. ep. 



.^^deg.ov. 



— b.c. 







Fig. loi 

 Metaplasia of fibroblasts of Pecten into ciliated epithelium. A piece of ovarian 

 tissue was grafted into the adductor muscle where a cyst was formed round it, 

 lined by an epithelium formed of fibroblasts. 1-4, stages in the transformation 

 of the fibroblasts into ciliated epithelium ; i , after 23 days ; 2, 26 days ; 3, 30 days ; 

 4, 98 days. b.c. blood corpuscles; cil.ep. ciliated epithelium; deg.vo. degene- 

 rating ovarian grafted tissue; fhl.lyr. fibroblast layer; msl.fbr. muscle fibres; 

 msl. nuc. nuclei of muscle cells. (From Gray, Experime?ital Cytology, Cambridge, 

 193 1, after G. H. Drew.) 



