NOTES AND MEMORANDA. 288 



tions can produce the same symptoms as the immediate 

 action in the stomach, rectum, or nervous system, Avhilst the 

 particles of cholera-ejections disinfected by carbolic acid 

 appear to be quite innoxious. 5. A current of air carries 

 with it small particles from non-disinfected ejections with 

 vegetate rapidly under favorable circumstances, whilst the 

 fungi from cholera-ejections disinfected by carbolic acid are 

 capable of propagation. 6. Cholera-ejections freed from form- 

 elements can produce, by their chemical constituents, the 

 same pathological effects as with their form-elements. — 

 W. Stirling, D.Sc, M.B.— Medical Record. 



Causes of Decay of Teeth. — These are not, according to 

 Leber and Rottenstein, internal or vital so much as external 

 and chemical. The process of decay begins from the surface, 

 and if it can be controlled or arrested at the surface it is 

 entirely controlled. The great causes of caries are two — 

 viz., acids and fungus found abundantly in the mouth, 

 Leptothrix hiiccalis. This latter agent is characterised by 

 certain microscopic appearances and by its reaction with 

 iodine and acids, which give to the elements of leptothri a 

 beautiful violet tinge. Under the microscope the fungus 

 appears as a grey, finely granular mass or matrix, Avith 

 filaments delicate and stiff, which erect themselves above 

 the surface of this granular substance so as to resemble an 

 uneven turf. The fungus attains its greatest size in the 

 interstices of the teeth. No one can deny nowadays the 

 action of even weak acids in dissolving the salts of the 

 enamel and the dentine, making the enamel, naturally 

 transparent, first white, opaque, and milky, and, in a more 

 advanced state, chalky, and the dentine more transparent 

 and softer, so as to be cut with a knife. The acids which 

 may actually effect the first changes in the production of 

 caries are such as are taken with food, or in medicines, or such 

 as are formed in the mouth itself by some abnormality in 

 our secretions., which should be alkaline, or by an acid fer- 

 mentation of particles of food. Acids play a primary part, 

 making the teeth porous and soft. In this state, the tissues 

 having lost their normal consistency, fungi penetrates both 

 the canaliculi of the enamel and of the dentine, and by their 

 proliferation produce softening and destructive effects much 

 more rapid than the action of acids alone is liable to accom- 

 plish. Huwditch, in examining forty persons of different 

 ])rofessions, and living different kinds of life, found in almost 

 all vegetable and animal parasites. The parasites Aveie 

 numerous in proportion to the neglect of cleanliness. The 



VOL. XIV. NEW SER. T 



