PREFACE TO THE FOURTH EDITION. 



IN previous Editions of this work I endeavoured, by the 

 use of small and large print, to distinguish between the 

 more important and stable portions of Physiology, which 

 ought to be made known to every one engaged in a 

 serious study of the science, and the less settled, often 

 controverted views which should be attacked by the more 

 advanced students only. Experience however has taught 

 me that the advantages of such a plan are more than 

 counterbalanced by its disadvantages. I especially felt 

 that the amount of space which I could fairly allow to 

 the small print paragraphs was wholly insufficient to 

 permit me to do justice to the conflicting views which 

 I strove, in them, to expound. 



In this Edition accordingly I have made no attempt 

 at any such distinction, and have used small print almost 

 exclusively for the description of methods and apparatus. 

 This step involving, as it necessarily did, the transference, 

 into the body of the work, of some of the statements 

 which previously had found their place in the small print 



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