SECTION TWO 



3. A third litter-mate (C) was subjected to fluorine for the 

 same period of time, but not injected with the dye until two hours 

 before sacrifice. 



4. All three animals were killed six weeks after administration 

 of fluorine. 



Note: Skeletal fluorosis was induced by adding sodium fluoride 

 to the drinking water to produce a fluoride concentration of 500 

 parts per million. 



5. The long bones of the rabbits were dissected. 



Results: 



The long bones of the non-fluoretic rabbit (A) were found to 

 be stained red upon their periosteal and endosteal surfaces; little 

 dye was found in the middle of the cortical compacta. 



The fluorotic rabbits (B and C) were found to have developed 

 exostoses upon the middle surfaces of the long bones. In rabbit B 

 the surfaces of the bone had taken up the dye before the exostoses 

 had developed, and the original cortical bone was separated from 

 the more recently formed fluorotic exostoses by a red line. The 

 exostoses themselves were unstained. 



In rabbit C, however, the exostoses bone had formed upon the 

 long bones before the dye had been injected, and it was found to 

 be heavily stained. 



Notes: 



{a) The author states that apparently the age of osteoid tissue 

 does not affect the dye uptake and the stainability of the matrices 

 depended solely upon their being non-mineralized and he goes on 

 to describe experimental work in support of this. 



{b) Other experimental work, is also described, in which 

 culture filtrates of Clostridium histolyticum containing varying 

 amounts of three proteinases, the ^, y, and S toxins (Hobbs, 1958) 

 were used for digesting undecalcified bone and the results indicate 

 that chlorazol fast pink stains collagen of the bone matrix without 

 denaturing it with respect to the B toxin of CI. histolyticum, 

 which is a specific collagenase. The author cites the works of 

 Oakley and Warrack (1950, 1958), who showed that while de- 

 natured forms of collagen (gelatine and azocoll) are attacked by 



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