of those who have taken part in these advances, made 

 practically within the last quarter of a century, are, 

 happily, still with us, that I have left this question 

 aside. I have dealt more with the past than with 

 the present, and only here and there, and, as it were, 

 incidentally, referred to some of the great living 

 " Apostles." 



I have endeavoured as often as possible to let 

 the authors speak for themselves. The quotations are 

 generally given in small type, with a reference to 

 their source. 



If I were to add a list of the works consulted, 

 it would be a long list. I have to acknowledge my 

 indebtedness to the writings of R. Willis, Lectures on 

 the History of Physiology, by Sir Michael Foster, to 

 some of the volumes of the Masters of Medicine 

 series, Medical Portrait (gallery, by T. J. Pettigrew, 

 Biographisches Lexikon, and the various Histories of 

 the Royal Society. Most of the facts and quotations 

 have been taken from the original sources. 



Long years ago, in Ludwig's Laboratory, situated 

 in the street then called Waisenhaus Strasse, now 

 called Liebig Strasse, it was my good fortune to make 

 the acquaintance of JOHN CLELAND, then of Galway, 

 and now Professor of Anatomy in the University of 

 Glasgow. Imprimis, .to him my best thanks, because, 

 through his friendship, I have enjoyed the privilege 

 of increasing my knowledge of the works of the older 

 Anatomists and Physiologists. Several of the illus- 

 trations are from works lent by him. Moreover, 



