VI PREFACE. 



The great object of the Editor has been to make the work as prac- 

 tical as possible for all classes of readers, by avoiding as much as 

 circumstances would permit those technical details which none but 

 the scientific reader would comprehend. It will therefore necessarily 

 follow that any lengthened anatomical details must be omitted, 

 although it is believed sufficient have been retained to enable the 

 general reader to understand the more important parts of the frame. 

 The same remark applies to the chapters on medicines and poisons. 



In conclusion, the Editor trusts that the alterations and additions 

 which have been made will tend to enhance the value of the work, 

 and render this the fourth edition equally worthy of the public 

 esteem and patronage which have been accorded to its predecessors. 



