2=J. 



PREFACE. 



IN preparing this work for younger students especial 

 pains have been taken to make it clear and simple. Sen- 

 tences, paragraphs, and chapters have been made short, 

 and a concise summary follows each chapter. So far as 

 possible technical terms have been avoided and English 

 words preferred to Latin, for instance, post-caval vein 

 instead of vena cava inferior, spinal bulb instead of medulla 

 oblongata, etc. The Latin form of the plural puzzles the 

 student who has not had Latin ; hence the English form 

 of the plural is used, as pleuras, ganglions, ciliums, vil- 

 luses, papillas, etc. 



The illustrations are made clear and distinct, and are 

 labeled directly ; that is, the detail labels are on, or very 

 close to, the part labeled, so that time and effort are 

 not needed to associate the thing and the name. A large 

 number of the illustrations are original. 



A few simple experiments are given ; for although much 

 less can be done than with older students, yet considerable 

 must be done if the subject is to be made clear. 



The subject of hygiene has received careful attention ; 

 for it must not be forgotten that the main object of this 

 study is that each pupil may learn how to take better care 

 of his own body. The author has tried not to give mere 

 arbitrary rules of health, to be blindly and implicitly fol- 

 lowed, but to base all precepts of hygiene on the general 

 principles of physiology, so that the pupil may understand 



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