July 22, 1892.] 



SCIENCE. 



55 



towards the expenses of publication, etc., and the work will un- 

 doubtedly be a most valuable contribution to the early history of 

 America. It is expected that it will leave the government print- 

 ing office early in August. 



— In a capital address on " tooth culture,"' delivered at the an- 

 nual meeting of the Eastern Counties Branch of the British Dental 

 Association, and printed in Lancet, Sir James Crichton-Browne 

 referred to a change which has taken place in bread, as one of the 

 causes of the increase of dental caries. So far as England is con- 

 cerned, this is essentially an age of white bread and fine flour, 

 and it is an a?e therefore in which we are no longer partaking, to 

 anything like the same amount that our ancestors did, of the bran 

 ■or husky parts of wheat, and so are deprived to a large degree of 

 -a chemical element which they contain — namely, fluorine. The 

 late Dr. George Wilson showed that fluorine is more widely dis- 

 tributed in nature than was before his time supposed, but still, as 

 .he pointed out, it is but sparingly present where it does occur, and 



the only channels by which it can apparently find its way into the 

 animal economy are through the siliceous stems of grasses and 

 the outer husks of grain, in which it exists in comparative abun- 

 dance. Analysis has proved that the enamel of the teeth contains 

 more fluorine, in the form of fluoride of calcium, thgn any other 

 part of the body, and fluorine might, indeed, be regarded as the 

 characteristic chemical constituent of this structure, the hardest 

 of all animal tissue, and containing 95 5 per cent of salts, against 

 73 per cent in the dentine. As this is so, it is clear that a supply 

 of fluorine, wdiile the development of the teeth is proceeding, is 

 essential to the proper formation of the enamel, and that any de- 

 ficiency in this respect must result in thin and inferior enamel. 

 Sir James Criohton-Brpwne thinks it well worthy of con.sideration 

 whether the reintroduction into our diet of a supply of fluorine in 

 some suitable natural form — and what form, he asks, can be 

 more suitable than that in which it exists in the pellicles of oru- 

 grain stuffs? — might not do something to fortify the teeth of the 

 next generation. 



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