TEETH. 



157 



and prepared to discharge its office. It is cut with certain angular 

 prominences upon its masticating surface, which must render the animal 

 disinclined to employ it on the instant of its development. This dis- 

 inclination allows a pause, during which the various structures can be 

 consolidated, and at the end of such brief space the prominences have 

 become blunted, while the organ, being firmly planted, is then ready for 

 mastication. Is it not surprising how a plain statement of facts can 

 reasonably account for that disinclination to feed which, to the groom's 

 mind, announces a state of disease that shall necessitate the employment 

 of burning iron to eradicate what the man styles "Lampas !" 



There remains, however, to account for that width and depth of jaw 

 by which the head of the youthful horse is distinguished. The reader 

 is requested to attentively inspect the last illustration. The size and 

 length of fang cannot fail to awaken his surprise. Nevertheless, if this 

 part be regarded it will be seen depicted as of a ragged, incomplete, and 

 apparently of a hollow condition. So, when the tooth has displaced the 

 temporary molar, and has taken its station within the mouth, it has still 

 to grow. The protruded portion may be consolidated; but the un- 

 finished extremity is denominated the cavity of the pulp. That pulp con- 

 sists of a fine bladder, on which ramify numerous blood-vessels ; but the 

 interior of which contains simply a clear fluid. This is the secreting 

 membrane of the tooth. Out of this watery 

 bag the wonderful chemistry of nature can ex- 

 tract the most condensed material that resides 

 within the strong body of a horse. 



Another feature of the above tooth, because 

 it balks expectation, can hardly fail to attract 

 notice. The dark hue of the outward covering, 

 being abhorrent to human notions of youth or 

 of purity, is generally attributed to dirt. The 

 tooth of the horse is, however, composed of 

 three substances : a tough and fibrous material, 

 called crusta petrosa ; a thin layer of crystalline 

 deposit, named enamel ; and a kind of compact 

 bone, spoken of as dentine. They occur accord- 

 ing to the order in which they are named. The 

 bone exhibits a yellow tinge, and is present in 

 the greatest quantity, for it forms the inner bulk 

 of the tooth. The crusta petrosa is a comparatively thick external en- 

 velope, being about five times the substance of the enamel, to which it is 

 an outward protection. The components are thrown into various con- 

 volutions; but the order alluded to is always preserved. The bone or 



SECTION OF A MOLAS 

 TOOTH. 



