24 COMPARATIVE DENTAL. ANATOMY 



gans, since they have the same function, — the 

 aeration of the blood, — bnt they are not the same 

 organs. Therefore, homology has reference to 

 community of origin, and analogy to similarity of 

 function only. 



Comparative Dental Anatomy is the study of 

 the teeth of lower animals as compared to man. 

 The observation and comparison of their forms 

 and functions will illustrate the understanding of 

 the human teeth, because the teeth of man can 

 only be studied scientifically by comparison with 

 lower forms of the same organs, — just as in study- 

 ing other organs, by the comparative method. 

 Thus homologies with the teeth of lower forms 

 can be demonstrated, and analogous structures 

 in other locations will throw light upon their vari- 

 ations, by these studies. This will illustrate the 

 principles which have controlled their growth 

 and organization, and explain the varied details 

 of function. 



The teeth of man have, in the course of their 

 evolution to present forms, passed through the 

 transitional stages common to all organs in all 

 animals. In consequence they, like other organs, 

 still retain many features that indicate relation- 

 ship with the teeth of lower animals. The teeth 

 of man have been much reduced in size and 

 strength, and are more or less rudimentary and 

 much less specialized, as compared with the highly 



