HISTORIC DEVELOPMENT OF IMMUNOLOGY 13 



on vertebrate and invertebrate anatomy are lit- 

 tle master-pieces of their kind. Masters of phys- 

 iology in the second half of the nineteenth cen- 

 tury were Helmholtz, Claude Bernard and Lud- 



Antonj van Leeuwenhoek (1632-1723). 



wig. In connection with the work of Bernard 

 we may follow the modern developments of the 

 physiology of digestion, of metabolism and of 

 the ductless glands. Recent knowledge of the 



