BONES. 397 



cold water, and afterwards kept for twenty-four hours in water, 

 nearly at the boiling point. The cartilage, from which the 

 earthy matter has been removed, is thus dissolved, and num- 

 berless minute vessels may be seen issuing from the undecom- 

 posed portion of bone, presenting a beautiful white velvety 

 appearance, which is injured by the least motion ; If the bone 

 when immersed in dilute hydrochloric acid is exposed to heat, 

 the chemical action is facilitated, and the bone develops car- 

 bonic acid and separates into fibrous lamellse, divisible in a 

 longitudinal direction, which, if they are sufficiently thin, possess 

 the property of polarizing light in the same manner as mica. 



When bone is submitted to thorough incineration, all the 

 organic portion is destroyed, and there remains nothing but 

 the earthy matter mixed with certain salts which have been 

 formed during the process of incineration, such as alkaline 

 sulphates and carbonates, and with free lime formed by the 

 expulsion of the carbonic acid from carbonate of lime. 



The carbonate of lime in bone is just the same as the natural 

 carbonate of lime ; the phosphate, on the other hand, consists 

 of 8 Ca O + 3 PO 5 , according toBerzeliusi ; and 3 Ca O + P O 5 , 

 according to Mitscherlich. In addition to these salts we find 

 small quantities of phosphate of magnesia and fluoride of cal- 

 cium, 2 and traces of the peroxides of iron and manganese. 



[An elaborate treatise on the Chemistry of Bone has been 

 recently published by Von Bibra. We extract the following 

 analyses : 



1 [Berzelius repeated the analysis of the salt last year, and found that its compo- 

 sition is rightly expressed. (Oefversigt af Kongl. Vat. Akad. Forhandlingar, 1844, 

 No. 6 ; or Liebig's und Wbhler's Aunalen, Feb. 1845.] 



3 [The presence of fluoride of calcium in bone has been denied by Rees (Phil. 

 Mag. Jan. 1840.) The researches of Daubeny and Middleton (Memoirs and Proceed- 

 ings of the Chemical Society of London, vol. 2, pp. 97 and 134) not only demonstrate 

 its almost constant occurrence both in recent and fossil bones, but point out that 

 ordinary water is the vehicle by which it is conveyed into the system. " With regard 

 to the statements of Rees," observes Von Bibra, " I put them to the proof, and found, 

 as was to be expected, that they were altogether incorrect. I used in these experi- 

 ments the human femur, humerus, and teeth. On treating large quantities of bone- 

 earth with sulphuric acid, I have obtained corrosions on glass sufficiently deep to be 

 felt with the finger-nail." (Chemische Untersuchungen iiber die Knochen und 

 Zahne, p. 103, Schweinfurt, 1844.)] 



