KXOHA.NGE OF PnOSTHOKTS TX IKETll 



] (V.) 



organic mat tor in 1h(^ c^namel is probably found 1o a large extent 

 in the above mentioned connective substance. Jn marsupials and 

 some rodents there are regular eanaliculi in the interprismatic sub- 

 stance. 



The central cavity of a tooth is occupied by a soft and very vascular 

 dental pulp, containing cells, blood-vessels, nerves, and fine connective- 

 tissue fibres. The cells are partly disseminated in the matrix and partly 

 form a stratum at the surface of the pulp. These superficial cells, the 

 odontoblasts, send out elongations into the tubules in the dentine. It is 

 through the intermediary of the pulp that constituents of the blood get 

 into the hard tissues of the teeth. 



Chemical composition of the teeth 



a) Dentine. 



On analysing a great number of dry human dentine samples Bowes 

 and Murray^ found a loss in weight of the fresh tissue on ignition 

 amounting to 29 — 29.7%. The losses on ignition found in some of 

 our experiments can be seen in Table 1, in which we have also 

 included for the sake of comparison the values found for the tibia 

 and jaw. 



Tablk 1. Albino Hat 2(Hl g 



The average values found for the chief constituents of the dentine by 

 Bowes and Murr.w^ are seen in Tabic 2. 



1 I. H. Bowos and y\. ^\. Mt^ray, (193(i) Biochem, J. 30, 1?)77, 



