VETERINARY DENTAL SURGERT. 29 



responds to a tooth and is divided from those adjoin, 

 ing by prolongations of connective tissues, covered 

 by the periodental membrane which passes across the 

 groove. This forms the tooth socket. From below 

 in the lower jaw and from above in the upper jaw a 

 papilla of connective tissue grows towards the follicle 

 which later on becomes the dentine organ being 

 covered by the enamel organ like a cap. 



At about the' fourteenth week of foetal life a 

 vascular tissue is developed about the enamel organ 

 and dentine germ Vhich becomes the dental sac. 

 .Several weeks_jater the papillae undergo a change 

 and assume the forms of the crowns of the teeth.^) 

 Small membranous lid-like coverings are developed 

 from the side of the follicle, corresponding in number 

 and shape with the table surface of the teeth. The 

 side of the follicles and the lid-like membrane close 

 and form sacs. Just previous to the closing of the 

 sacs of the milk teeth, a depression is noticed behind 

 and inside of each follicle. These are the cavities of 

 reserve which eventually form follicles for the de- 

 velopment of the permanent teeth which replace the 

 temporary. ( The papilla enlarges and is converted 

 into the pulp which resembles the crown of the 

 tooth. ) The process of Calcification now begins";) a 

 thin layer of dentine is developed from the covering 

 membrane on the outer part of the pulp, layer 

 after layer being deposited from the substance of 



