PREFACE 



THE following Treatises are devoted to the consideration of the structure of Plants and 

 Animals ; and it has been the aim of the authors to write with scientific accuracy, and 

 with sufficient detail, without introducing discussion upon contested subjects. They 

 trust that the work will be found intelligible to the unlearned, and instructive to those 

 also who have obtained an elementary knowledge of the subjects. 



Occasional observations will be met with, by which the reader is reminded that 

 Plants and Animals are not only parts of the same great Creation ; but that so closely 

 are some plants associated with the so-called higher kingdom, that no definite line of 

 demarcation can be drawn between them. It is for this reason that the reader is 

 advised to study Botany in connexion with Zoology ; and it is probable that a closci 

 acquaintance with the structure and functions of certain parts of plants will ultimately 

 enable us to trace more correct as well as more striking resemblances between the 

 members of the two kingdoms than have as yet been conceived. For example, no 

 nerves, or analogues of nerves, have as yet been found in plants ; and yet it is quite 

 clear that not only is a low degree of vital sensibility as universal in plants as in 

 animals ; but that in certain instances, as in the sensitive plant, it is developed to a 

 far greater extent than is perceptible in animals taken from the lowest point in the 

 scale of animal life. 



This mode of investigation will give greater breadth and interest to the study of 

 Natural History than the more simple and yet more difiicult one of studying the 

 parts of plants or of animals as detached points bound together by no universal law ; 

 and it is one, moreover, which tends to train the mind to habits of reflection as well 

 as of observation. The authors have endeavoured to aid the mind in this search by 

 introducing a very large number of microscopic and other illustrative engravings, which 

 have the merit of showing the extreme beauty and elegance of design existing in 

 the composition of plants, and offer many new points for analogical comparison 

 with the exquisitely minute structures of animals. A microscope is now as necessary 

 to tiie naturalist as a telescope to the astronomer. 



