in Becent as ?vell as in Fossil Bones, 293 



mens of fossil and recent bones of which I made a rough analysis, 

 that from Stouesfield, which was the oldest of any, having been im- 

 bedded in a .secondary rock belonging to the oolite formation, lost, by 

 exposure to ajieat of 212°, 4*2 per cent. ; by a further heat of about 

 500°, 5*0 per cent, more, and by increasing the temperature to a red 

 heat, only 1-8 percent, in addition, 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 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 13.9, 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 per cent, of 

 water, and 1 1 animal matter ; and the human tibia, which had been 

 kept in an anatom.ical 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 m certain parts of the 

 bone, and for this reason may allow of a more ready disengagement 

 from it of the fluoric acid which it contains, as an ingredient. 



That a certain alteration in the arrangement of the earthy particles 

 of a bone does occasionally take place after its deposition, is evinced 

 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 phosphate appears, in some instances, to have se- 

 parated into two distinct compounds, crystals of apatite being recog- 

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

 they conceive to have arisen from the segregation of the tribasic 

 from the bibasic compound. 



Will not this latter fact also help us towards an understanding 

 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 ingredient ? 



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

 crystallization should operate as a sort of antagonist force to the 

 process of assimilation, so that no material can be fitted to enter into 

 the fabric of a living body, between w^hose particles the natural force 

 of polarity operates with all its energy. Hence, according to Dr Prout, 

 the use of the infinitesimal small portions of foreign inorganic 

 matter interposed between the particles of most bodies, which form 

 the constituents of vegetable or animal organization ; and although 

 it may be true, as has been suggested by Von Buch, that the very 

 prismatic form which belongs to the phosphate of lime as a mineral 

 species, adapts it for the fibrous structure of bone better than other 

 earthy compounds, in which the axis of crystallization is equal in 



