THE BIRTH OF HISTOLOGY 



175 



parliament. He assisted in molding the cell-theory into 

 better form, and in 1858 jjublished a work on Cellular 

 PatJwlogy, which applic^l the cell-theory to diseased tissues. 

 It is to be remembered that Bichat was a medical man, in- 

 tensely interested in pathological, or diseased, tissues, and we 



Fig. 52. — Franz Leydig, 1821-190S (April). 

 Courtesy of Dr. Wm. M. Wheeler. 



see in Virchow the one who especially extended Bichat's work 

 on the side of abnormal histology. A^irchow's name is asso- 

 ciated also with the beginning of the idea of germinal conti- 

 nuity, which is the basis of ])iological ideas regarding hered- 

 ity (see, further. Chapter XV). 



Leydig. — Franz Leydig (Fig. 52) was early in the field 

 as a histologist with his handbook (LcJirbuch dcr Hisiologie 



