SYSTEMATIC SYNTHESIS OF TISSUES INTO ORGANS. 287 



dissolved and act through the cellular and basement lay- 

 ers that cover the papillae, upon their tactile corpuscles, 

 in which the nerves of taste commence. 



Remark. How they act, and why one substance produces a differ- 

 ent effect from another, is not known. 



723. THE TEETH SEKVE AN ADMIRABLE PURPOSE for 

 grinding the substances to be tasted, and the SALIVA is 

 equally applicable for dissolving them. 



724. THE SENSE OF TASTE is in some way ASSOCI- 

 ATED with that of smell, since while the nose is closed 

 many substances become tasteless. The rationale of this 

 is not understood. 



Remark. The value of this sense will be further illustrated when the 

 apparatus is made up. 



The Nose as an Organ of Sense. 



725. THE NOSE is PRIMARILY for the passage of air, 

 and nerves of common sensation extend from all its 

 parts, the nerves of smell being superadded to certain 



portions. 



FIG. 195. 



Fig. 195 represents a 

 perpendicular section of 

 the bones of the nose a 

 little to the right of the 

 central partition, exhibit- 

 ing, 14, the front point of 

 the floor, and 4, the roof of 

 the nose, between them be- 

 ing the passage through, 

 in the outside of which is 

 hanging 9, the inferior tur- 

 binated or spongy bone, 

 slightly coiled, as its name 

 signifies ; 8, the middle ; 7, 

 the superior turbinated or spongy process. At 3, a sinus or cavity in the 

 sphenoid is seen opening at 10 ; 4 is the frontal sinus, opening into the up- 

 per part of the nasal cavity; 12 is the opening into a sinus in the upper 

 jaw-bone directly above the eye-tooth. (Other cavities not shown are in the 

 roof of the nose, opening into it.) 



723. For what do ? What is the use of the ? 724. How is - ? 725. What 

 ia ? Describe Fig. 195. 



