i?4 NATURAL THEOLOaY. 



eated with one another, that they cannot be traced by the 

 nicest dissection ; nevertheless — which is a great perfection 

 of the organ — neither the number nor the complexity, nor 

 what might seem to be the entanglement of its fibres, in any- 

 wise impede its motion, or render the determination or suc« 

 cess of its efibrts uncertain, 



1 here entreat the reader's permission to step a little out 

 of my way, to consider the 'parU of the mouth in some of 

 their other properties. It has been said, and that by an 

 eminent physiologist, that whenever nature attempts to 

 work two or more purposes by one instrument, she does both 

 or all • imperfectly. Is this true of the tongue, regarded as 

 an instrument of speech and of taste, or regarded as an 

 instrument of speech, of taste, and of deglutition ? So much 

 otherwise, that many persons, that is to say, nine hundred 

 and ninety-nine persons out of a thousand, by the instrumen- 

 tality of this one organ, talk and taste and swallow very 

 weU. In fact, the constant warmth and moisture of the 

 tongue, the thinness of the skin, the papilla) upon its surface, 

 qualify this organ for its office of tasting, as much as its 

 inextricable multiplicity of fibres do for 1 he rapid movements 

 Mdiich are necessary to speech. Animals which feed upon 

 grass have their tongues covered with a perforated skin, so 

 as to admit the dissolved food to the papillae underneath, 

 which in the mean time remain defended from the rough 

 action of the unbruised spiculse. 



There are brought together w^ithin the cavity of the 

 mouth more distinct uses, and parts executing more distinct 

 offices, than I think can be found lying so near to one another, 

 or within the same compass, in any other portion of the 

 body : namely, teeth of different shape, first for cutting, sec 

 ondly for grinding ; muscles, most artificially disposed foi 

 carrying on the compound motion of the lower jaw, half lat- 

 eral and half vertical, by which the mill is worked ; foun- 

 tains of saliva, springing up in difTerent parts of the cavit\ 



