vi AUTHOR'S PREFACE. 



difficult to the majority of those who are engaged in practice, to 

 obtain in the subjects treated on in these lectures that amount of 

 personal experience which alone can guarantee a certain degree of 

 accuracy of judgment. Day by day do those who are obliged to 

 consume their best energies in the frequently so toilsome and so ex- 

 hausting routine of practice find it becoming less and less possible for 

 them, not only to closely examine, but even to understand the more 

 recent medical works. For even the language of medicine is gra- 

 dually assuming another appearance ; well-known processes to which 

 the prevailing system had assigned a certain place and name in the 

 circle of our thoughts, change with the dissolution of the system 

 their position and their denomination. When a certain action is 

 transferred from the nerves, blood, or vessels to the tissues, when a 

 passive process is recognized to be an active one, an exudation to be 

 a proliferation, then it becomes absolutely necessary to choose other 

 expressions whereby these actions, processes, and products shall be 

 designated ; and in proportion as our knowledge of the more deli- 

 cate modes, in which the processes of life are carried on, becomes 

 more perfect, just in that proportion must the new denominations also 

 be adapted to this more delicate ground-work of our knowledge. 



It would not be easy for any one to attempt to carry out the 

 necessary reform in medical opinion with more respect for tradition 

 than I have made it my endeavour to observe. Still my own expe- 

 rience has taught me that even in this there is a certain limit. Too 

 great respect is a real fault, for it favours confusion ; a well-selected 

 expression renders at once accessible to the understanding of all, 

 what, without it, efforts prolonged for years would be able to render 

 intelligible at most only to a few. As examples I will cite the terms, 

 parenchymatous inflammation, thrombosis and embolia, leukaemia 

 and ichorrhaemia, osteoid and mucous tissue, cheesy and amyloid 

 metamorphosis, and substitution of tissues. New names cannot be 

 avoided, where actual additions to experimental (empirical) know- 

 ledge are being treated of. 



On the other hand, I have already often been reproached with 

 endeavouring to rehabilitate antiquated views in modern science. 

 In respect to this I can, I think, say with a safe conscience that I am 

 just as little inclined to restore Galen and Paracelsus to the position 



