32 TOOTH-GERMS. 



future temporary teeth are about the size of small 

 peas. They will bear some pressure between the 

 fingers, the indentations springing back like those 

 of an India-rubber ball. 



The nature of tooth-germs and the development of 

 teeth have been studied with some diligence by scien- 

 tific men Dr. John Hunter, it is said, making the first 

 important discoveries in connection with the science. 

 The discussion of this interesting and, to students, 

 useful subject is left to these men. There is some 

 conflict in their views, but it should be remembered 

 that the extracts reflect the opinions of men from 

 Hunter's time (over a century ago), to 1876. The de- 

 velopment of tooth-germs being the same in principle 

 (though different in detail) in all mammals, the matter 

 which follows (as has been said of that in the "Intro- 

 duction"), is as applicable to the horse as to man. 



In the Introduction to his " Odontography " (Lon- 

 don, 1844), Prof. Richard Owen says: 



" In the development of a tooth a matrix of equal 

 complexity was first recognized to be concerned by 

 John Hunter, the several parts of this matrix being 

 first distinctly indicated in the ' Natural History of 

 the Human Teeth.' * * * Hunter has been gen- 

 erally regarded by physiologists as being the author of 

 the theory that the pulp stood to the tooth-bone in the 

 relation of a gland to its secretion ; that the formative 

 virtue of the pulp resided in its surface ; that the den- 

 tine was deposited upon and by the formative or secre- 

 tive surface in successive layers, and that the pulp, 

 exhausted, as it were, by its secretive activity, dimin- 

 ished in size as the formation of the tooth proceeded, 

 except in certain species, in which it was persistent, 



