PREFACE. IX 



accrues to science : nor can simple refer- 

 ence to a particular class, from external 

 conformation, be accounted of equal import- 

 ance to watching the properties disclosed 

 by living nature. Hence the great neces- 

 sity that animals shall be preserved in that 

 condition where all the vital functions, un- 

 restrained, can be fully displayed ; where 

 we shall be enabled to behold the united 

 operation of instinct and organization. 

 Though reasoning on facts which can ad- 

 mit of no mistake be thus reduced to the 

 result of time and industry, our cares are 

 rewarded by banishing precipitation, which 

 is ever prejudicial to philosophical enquiry, 

 and hostile to the discovery of truth. 



