XIV INTRODUCTION. 



to the principal aim which I had in view. When- 

 ever I was speaking of scientific matters I never 

 allowed myself in the slightest degree to sacrifice 

 the substance to the form. Here I was anxious to 

 act the part of the zoologist as rigidly as if I had 

 been engaged in compiling a work for my brother 

 zoologists. The facts which I have brought forward 

 in these Rambles may be found either in my own 

 memoirs or in the scientific works of others, whilst 

 the ideas which I have here developed are precisely 

 the same as those which I have at all times advo- 

 cated. Considered in this respect, these volumes 

 might be entitled General Essays on Zoology and 

 Physiology. In the notes which I have added to the 

 present edition of these Rambles I have entered 

 somewhat more freely into the technical character 

 of some of the questions under consideration; I 

 have given references to a large number of dif- 

 ferent works and memoirs ; and, finally, I have ap- 

 pended notices, which are of necessity very short, 

 regarding the lives and the principal labours of the 

 authors whom I have had occasion to quote. 



If I should be blamed for spending time upon this 

 attempt to popularise science which I might have 

 devoted to original researches, I would venture to 

 urge in extenuation that La Place wrote his Expo- 

 sition du Systtme du Monde, Cuvier his Discours sur 

 les Revolutions du Globe, Arago his Notices, Flourens 

 his Etudes and his Histoires, and Humboldt his 



