388 THE HISTORY OF BIOLOGY 



common to all. This explains to a certain extent how it was that so many- 

 scientists of independent and original thought could be trained in this 

 school, men such as Schwann and Virchow, Henle, Remak, Kolliker, Du 

 Bois-Reymond and Helmholtz; the same circumstance may also explain the 

 widely differing lines of research upon which they entered, but it naturally 

 confirms also the extraordinary many-sidedness of the master himself. Thus, 

 microscopy and cytology as well as experimental physiology in its most 

 strictly limited sense were here developed side by side. We shall now con- 

 sider, to begin with, the development of the two first-mentioned branches 

 of research. 



