PREFACE. 
The greatest part of the following Work was 
originally published in the form of successive papers 
in ‘ Excelsior.” Several entire chapters have, how- 
ever, been added, to make the survey of the animate 
creation more complete, and the whole has been care- 
fully revised. The design of the author has been to 
present to general readers, who have not the time or 
inclination for the study of works more elaborately 
technical, a glance at the more interesting phenomena 
ofxhimal life ; and, in particular, the diversities of 
tiucture that the physiologist recognises as he travels 
up the complex scale, and the wondrous adaptation 
which exists between these and the various functions, 
habits, and instincts of living beings. And, finally, 
he has endeavoured, unobtrusively, to lead the mind 
of the reader to God, and to link the perfections of 
creation with His glorious and immutable attributes. 
London, December 18 50. 
