PREFACE TO THE FIRST EDITION. XI 



guide to those who are inclined to follow upon the same 

 road. A number of common and readily obtainable plants 

 and animals have been selected in such a manner as to 

 exemplify the leading modifications of structure which are 

 met with in the vegetable and animal worlds. A brief 

 description of each is given; and the description is followed 

 by such detailed instructions as, it is hoped, will enable the 

 student to know, of his own knowledge, the chief facts 

 mentioned in the account of the animal or plant. The 

 terms used in Biology will thus be represented by clear and 

 definite images of the things to which they apply ; a com- 

 prehensive, and yet not vague, conception of the phenomena 

 of Life will be obtained ; and a firm foundation upon which 

 to build up special knowledge will be laid. 



The chief labour in drawing up these instructions has 

 fallen upon Dr Martin. For the general plan used, and 

 the descriptions of the several plants and animals, I am 

 responsible ; but I am indebted for many valuable sugges- 

 tions and criticisms from the botanical side to my friend 

 Prof. Thiselton Dyer. 



T. H. H. 



LONDON, 



September, 1875. 



