Introduction 3 



ation. There is every indication that histochemistry is emerg- 

 ing now as an independent discipHne with its own theoreti- 

 cal background, methods, and special problems, just as was 

 the case with biochemistry shortly after the turn of the 

 century. 



Urban & Schwarzenberg, 1912); Prenant, A.: Rev. gen. d. sc, 32:581, 1921; 

 Parat, M.: Biol. Rev., 2:285, 1927; Patzelt, V.: Animale Histochemie, in 

 Klein and Strabinger's Fortschritte der Microchemie (Leipzig and Vienna: 

 F. Deuticke, 1928); and Klein, G.: Praktikum der Histochemie (Berlin: 

 J. Springer, 1929). 



