NERVES TO ODONTOBLASTS, AND ON THE GROWTH OF DENTINE. 



329 



Measurements of Lower Canine Teeth in Cats. 



Total length of tooth, 

 Greatest length of pulp cavity, 

 Greatest breadth of pulp cavity, 

 Thickness of dentine at middle of tooth, 

 Greatest thickness of dentine at crown, 

 Diameter of dentinal tubules at origin, 



Width of intertubular dentine, 



Newly-born. 



I inch 0-196 



* » 0-18 

 rh » 0-056 

 006 



1200 " 



eV „ 00166 



0'0000589 



17 0-0 '> 



fa „ 0-000235 



One Month Old. 



iff inch 0-36,6 

 0-32 

 0-074 



2 3 V. 



3 7 

 500 ' 



2 5(X 



_2 3 

 50~<T ' 



17 07JTT ) 



0036 

 0-046 

 0-0000589 



^Viy » 0-000235 



Adult. 



Jfo inch 0-59 



i 



2 5 » 



0-5 

 0-04 

 006 

 0-09 



at base ia ^ oTr inch 

 0-00U0833 



at crown 



OTjTJ 



0-000037 



inch 



at base , ./ . inch 



0-00U235 

 0-000166 



at crown $-£$-$ inch 



(1) This table shows that the lower canine tooth of the adult cat is fully three 



times as long as it is in the newly-born kitten. 



(2) The pulp cavity grows longer in the same proportion. 



(3) As regards the width of the pulp cavity, it seems first to increase in breadth, 



but in the adult tooth the breadth is less than in the newly-born kitten ; but I 

 shall discuss this later on. 



(4) At the middle of the tooth the dentine increases to a thickness ten times 



greater than in the newly-born kitten ; while at the crown it increases to about 

 six times. 



(5) The diameter of the dentinal tubules was the same in the young kittens. In 



the adult cat, however, the tubules at the base of the tooth are one-half larger 

 than those of the younger cats ; but near the crown their diameter decreases 

 greatly, being a half less than in the younger cats, and even two-and-a-half 

 times smaller than at the base of the same adult tooth. 



(6) The width of the intertubular substance remains the same in the canines of 



kittens and also at the base of the adult tooth. At the crown of the adult 

 tooth, however, it is only three-fourths of the breadth of what it is at the root, 

 or in the younger teeth. 



Before describing how this tooth grows, I must first call particular attention to a 

 fact on which the importance of this inquiry rests, viz., this, that the canine tooth of 

 young kittens is not flask-shaped, but merely conical, resembling the extinguisher of 

 a candle, the sides (Fig. 10) sloping downwards and outwards from the crown. This 

 originally conical tooth increases in size as follows : 



VOL. XXXVI. PART II. (NO. 14). 3 E 



