PREFACE. XXI 



whoj if the drawings &c. had been to be paid 

 for, must necessarily have contented themselves 

 with giving a much smaller number. 



To Alexander MacLeay, Esq. they are un- 

 der particular obligations, both for the warm in- 

 terest he has all along taken in the work, the ju- 

 dicious advice he has on many occasions given, 

 the free access in which he has indulged the 

 authors to his unrivalled cabinet and well-stored 

 library, and the numerous other attentions and 

 accom.modations by which he has materially as- 

 sisted them in its progress. 



To the other friends who have kindly aided 

 them in this undertaking in any way, they beg 

 here to offer their best thanks. 



It now only remains that they should assign 

 their reasons for sending the work into the world, 

 contrary to their original intentions, in an imper- 

 fect state, by the publication of the first volume 

 only. One inducement to this course has been the 

 occurrence of unexpected interruptions, which, 

 though the bulk of the work has been long writ- 

 ten, have hitherto precluded the completion of the 

 entire plan ; but their principal reason has been 

 the wish to render the physiological and anatomi- 

 cal departments more perfect by the consultation 

 of various continental works published within the 

 last six or eight years, now for the first time ac- 



