vi PREFACE. 



Teeth. The execution of this part of the 'Circle' has 

 been confided to that great philosophical anatomist who 

 has so distinguished himself in working out the true 

 principles of Osteology — principles which will doubtless 

 soon be applied to the nomenclature and description of 

 every branch of Anatomical Science. Avoiding the com- 

 mon practice of intrustiug the special essays to literary 

 compilers and abridgers, it has been part of the design 

 of the work — hitherto with success — to engage, in the 

 important task of teaching, those master-spirits who have 

 in their day effected the greatest improvements, and made 

 the most decided advances, in their respective depart- 

 ments of science. The result has been, as is especially 

 shown in the Essay on the Principal Forms of the Skeleton^ 

 an original exposition of the principles of Anatomical 

 Science, and of the most important results that have been 

 attained by its latest cultivator; such exposition being 

 succinct without any important omission, and as clear 

 and comprehensible as is consistent with the inevitable 

 use of technical terms. 



"New and clearly defined ideas must be expressed by 

 their appropriate signs. The explanation of the sign 

 teaches the nature of the idea. Without learning and 

 understanding the technical terms of a science, that sci- 

 ence cannot be comprehended. The terms seem 'hard' 

 only while the ideas which they represent are not under- 

 stood. We listen with pleasure and surprise to the glib 

 facility with which the working classes, admitted in 



