().jS G. N. JENKINS AND C. DAWES 



though tlie low concentration of citrate as compared with lactate 

 produced by bone in vitro tends to minimize its importance. 



3. It is speculated that even small amounts of citrate might be 

 important in bone if they were localized in sites of resorption such 

 as those within or in the immediate vicinity of the osteoclasts. 

 Evidence is reviewed that citrate may enter the bone crystal and 

 increase its solubility. 



4. The suggestions on the possible role of chelation in dental 

 caries made by Schatz et at. are described and the evidence for 

 them is critically reviewed. 



5. It is concluded that, although there are gaps in the chain of 

 evidence for both the acid and the chelation theories, most of the 

 evidence supports acid as the means of decalcification in caries. 



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