366 French National Institufe. 



detrition is also convex. The contrary is the case, in these 

 two respects, with the lower jaw. 



A still more striking character may be inferred from the 

 direction of the lamina?, with respect to the corona on the 

 triturating part. 



Those from below are inclined backwards; that is to say, 

 the acute angle they form with the plane of trituration is 

 directed forward, at least in their radical part; for the sum- 

 mits of the anterior laminae are bent a little backward. 



Those from above, on the contrary, are inclined forward, 

 or the acute angle they form with the plane of trituration is 

 directed backward. 



It is always easy to distinguish the back of the tooth from 

 the front : the trituraiion cutting much more forward than 

 backward, it is the end the niost deeply worn down of the 

 corona, which is always the anterior. 



It must be remarked, however, that the inclination of the 

 laminae upon the corona diminishes at the two jaws in pro- 

 portion as the detrition increases. The posterior laminae, 

 ■which are not so slowly worn down, are now worn a little faster, 

 because, their development towards the root continuing when 

 that of the anterior laminae has ceased, they are pushed out- 

 wards with more force : whence it happens that the tablet 

 of detrition becomes more and more perpendicular to the 

 direction of the laminie. 



We also distmguish the teeth belonging to each side, be- 

 cause they are convex to their internal face, and a little con" 

 cave to the external one. 



[To be continued.] 



LX. Proceedings of Learned Societies. 



FRENCH KATIONAL INSTITUTE. 

 [Continued from p. 284.] 



JVl. DE Beauvois entertains similar ideas upon the iin" 

 pregnation of mushrooms. 



Various parts of these plants, like the laminae of the aga- 

 rics. 



