74 SPECIAL HISTOLOGY. 



course of caries is, that the discoloured spots of the cuticle of the 

 enamel, covered with living and growing organisms (infusorial 

 animalcules, similar to a Vibrio, which Ficinus calls Denticola, 

 mucedinous fungi (Erdl, Klenke, Tomes), similar to those 

 which are found upon the tongue, and which Ficinus wrongly 

 refers to the Denticolts) first lose their calcareous salts, and 

 then break up into angular, cellular pieces, as if they had been 

 treated with hydrochloric acid. The decay then penetrates 

 through the enamel to the dentine, always first softening it, so 

 that it yields not more than 10 per cent, of ash (Ficinus), and then 

 decomposing it. The dentine is more affected by this process 

 than the enamel, its canal first becoming filled with the fluids 

 proceeding from its decomposition, which may reach the pulp 

 and give rise to pain, unless, as Tomes found, the dentinal 

 canals in the neighbouring healthy portions become obliterated 

 by deposits, or the pulp is protected by new masses of den- 

 tine developed in the cavity 1 (Ficinus, Tomes). Eventually a 

 brownish deposit takes place in the tubules and then the in- 

 termediate substance becomes completely broken up. In this 

 manner the process of decomposition extends further and 

 further, until at last the crown collapses, the root also be- 

 coming dissolved and finally falling out. 



In jaundice, the teeth not uncommonly assume a yellow 

 colour, which is occasionally almost as intense as in the skin, 

 and in asphyxiated persons they are said frequently to be 

 red ; both facts being explicable only by the supposition that 

 the colouring matter of the bile and of the blood transudes into 

 the dentinal tubuli. In rachitis the teeth remain unaffected. 

 In the mucus upon the teeth, an abundant growth of the 

 mucedinous fungi which have been mentioned, is always to be 

 met with in a finely granular matrix, surrounding mucus- or 

 epithelium- corpuscles ; besides which we find the infusoria of 

 carious teeth and the earthy deposits of the oral fluids. If this 



1 [" It is worthy of mention, also, that in the teeth of the hare, the sow, and the 

 stag, especially in the molars, stony masses are constantly found. They are semi- 

 transparent, for the most part oval and rounded bodies, situated in the axis of the 

 dental pulp, towards its apex, in irregular rows, never extending the whole length of 

 the dental pulp, hut only to a greater or less distance from the coronal extremity." 

 Raschkow, Meletemata, &c, cited and translated in Nasmyth's ' Researches,' 

 (1839), p. 139.] 



