128 Dr. Daubeny on Fluorine in Bo7ies. 



bedded in a secondary rock belonging to the oolite forma- 

 tion, lost, by exposure to a heat of 212°, 4-2 per cent. ; by a 

 further heat of about 500°, 5*0 per cent, more, and by increa- 

 sing the temperature to a red heat only ] '8 per cent, in addi- 

 tion, the latter probably representing very nearly the amount 

 of animal matter remaining, the two former numbers the water 

 retained within the bone. 



Proceeding upon the same data, the bone from the tertiary 

 rocks of the Paris basin, next in the order of antiquity, would 

 contain 10 per cent, of water, 2 of animal matter; the bone 

 from Gailenreuth, water 139, animal matter 5*0; that from 

 Kirkdale 12*5 water, 11 animal matter; whereas the recent 

 bone picked up in the Botanic Garden contained, even when 

 dry externally, about 30 percent, of water and 11 animal 

 matter; and the human tibia, which had been kept in an 

 anatomical cabinet for a certain time, gave out 23 per cent, of 

 water and 17 of animal matter. 



It may also be suggested, as a possible explanation, that the 

 fluoride of calcium distributed through the mass has in the 

 course of time become collected into little nuclei in certain 

 parts of the bone, and for this reason may allow of a more 

 ready disengagement from it of the fluoric acid which it con- 

 tains as an ingredient. 



That a certain alteration in the arrangement of the earthy 

 particles of a bone does occasionally take place after its de- 

 position, is evidenced from the curious observations by Messrs. 

 Girardin and Preisser, in the memoir which has been already 

 referred to, as these gentlemen state, that the bone-earth phos- 

 phate appears in some instances to have separated into two 

 distinct compounds, crystals of apatite being recognised by 

 them in some of the fossil bones in their possession, which 

 they conceive to have arisen from the segregation of the tri- 

 basic from the bibasic compound. 



Will not this latter fact also help us towai'ds an under- 

 standing of the function which fluate of lime may fulfil in the 

 structure of bones, and likewise of the peculiar adaptation of 

 the bone-earth phosphate to serve as its prevailing earthy in- 

 gredient? 



It seems a general law in both kingdoms of organic nature, 

 that crystallization should operate as a sort of antagonist force 

 to the processes of assimilation, so that no material can be 

 fitted to enter into the fabric of a living body, between whose 

 particles the natural force of polarity operates with all its 

 energy. Hence, according to Dr. Prout, the use of the infi- 

 nitesimal portions of foreign inorganic matter interposed be- 

 tween the particles of most bodies which form the consti- 

 tuents of vegetable or animal organization ; and although it 



