124 Dr. Daubeny on the occurrence of 



contain as a constant ingredient a minute quantity of fluoride 

 of calcium, inasmuch as its presence is vouched for by them, 

 in recent as well as in fossil bones, and in the teeth of mam- 

 malia, as well as in other parts of their osseous structure. 



Here however I was compelled to pause, by observing the 

 contrary statements put forth by other able chemists relative 

 to this point; Fourcroy and Vauquelin having, previously to 

 the researches of Berzelius, denied the existence of fluorine 

 in recent bones, and Dr. Rees having, subsequently to them, 

 in a memoir drawn up under a full knowledge of what had 

 been done before, arrived at a conclusion equally opposed to 

 that of the Swedish philosopher*; one too which has been 

 since corroborated in a communication relative to the com- 

 position of bones made to the French Institute by Messrs. 

 Girardin and Preisser of Rouen, and lately published in the 

 Comptes Rendusf. 



As however none of these gentlemen appear to dispute that 

 fluorine does occur in Jbssil bones generally, the conclusion 

 they have arrived at leaves the subject, it must be confessed, 

 encumbered with greater difficulties than before, for as all 

 sound chemical analogies stand opposed to the admission of 

 the idea, that fluorine can have been generated from the other 

 constituents, during any process of decay or alteration that 

 might have occurred in it, during the ages that had elapsed 

 since it formed a part of the living structure, we should be 

 driven to the belief, that the fluoride of calcium contained in 

 bone had filtered in from without, — a conjecture which, al- 

 though perfectly plausible, if the occurrence of this ingredient 

 had been casual, or had been limited to bones found in rocks 

 of a certain age or composition, seemed rather a violent one, 

 when extended to those of all ages and formations, being 

 scarcely reconcileable with the rarity of the mineral itself in 

 the waters of springs, and its sparing solubility in most re- 

 agents. 



These difficulties that occurred to my mind, no less than 

 the weight 1 attached to the positive testimony of the great 

 Swedish chemist in favour of the existence of fluorine in re- 

 cent bones, induced me to consider, whether it might not be 

 possible that certain circumstances had operated in the mode 

 of conducting the experiment, by which the presence of fluo- 

 rine in the hands of the chemists who adopt the opposite con- 

 clusion escaped detection. 



And on further investigation it appeared to me, that two 

 ingredients naturally present in recent bones might have in- 

 terfered with the result in the instances alluded to. 



* See Phil. Mag. S. 3. vol. xv. p. 558.— Edit. 

 t Ibid. S. 3. vol. xxiv. p. 154.— Edit. 



