PROCESS OF TEETHING. 



123 



The five dark 



Fig. 17. 



Fig. 18. 



Fig. 17 represents a grinder sawed across, 

 spots represent bony matter ; the parts 

 covered with lines, enamel ; and the 

 white spaces, a strong hony cement, 

 uniting the other portions of the teeth. 



At the completion of the first year, a 

 fourth grinder usually comes up, and 

 the yearling has then, or soon after- 

 wards, six nippers, and four grinders 

 above and below in each jaw, which, 

 with the alteration in the appearance 

 of the nippers that we have just described, will enable us to cal- 

 culate nearly the age of the foal, suject to some variations aris- 

 ing from the period of weaning, and the nature of the food. 



At the age of one year and a-half, the mark in the central 

 nippers viall be much shorter and 

 fainter ; that in the two other pairs 

 wUl have undergone an evident 

 change, and all the nippers will be 

 flat. 



At two years this vidll be more 

 manifest. The accompanying cut 

 (Fig 18,) deserves attention, as giv- 

 ing an accurate represention of the 

 nippers in the lower jaw of a two- 

 years-old colt. 



About this period a fifth grinder 

 will appear, and now, likewise, will 

 3ommence another process. The 

 first teeth are adapted to the size and wants of the young animal 

 They are sufficiently large to occupy and fill the colt's jaws ; Lul 

 when these bones have expanded with the increasing growth of 

 the animal, the teeth are separated too far from each other to be 

 useful, and another and larger set is required. The second teeth 

 then begin to push up from below, and the fangs of the first are 

 absorbed, until the former approach the surface of the gum, 

 when they drop out. Where the temporary teeth do not rise 

 immediately under the milk-teeth, but by their sides, the latter 

 being pressed sideway, are absorbed throughout their whole 

 length. They grow narrow, are pushed out of place, and cause 

 inconvenience to the gums, and sometimes the cheek. They 

 are then called wolf's-teeth, and they should be extracted.* 



The teeth which first appeared are first renewed, and there- 



* Note by Mr. Spooner. — Although irregularities of the teeth sometimes 

 occur, as mentioned in the text, yet the wolves' teeth see generally two 

 very small supplementary teeth appearing in fi'ont of the molar teeth ; and, 



