OSSIFICATIONS. 579 



logy, that they consisted chiefly of phosphate of lime, and Dr 

 Wollaston proved the truth of this opinion by a chemical analy- 

 sis in 1797.* He dissolved some of the sand in nitric acid, and 

 evaporated the solution. Small needleform crystals of phosphate 

 of lime made their appearance. 



M. Lassaigne analyzed a concretion from the brain of a horse, 

 It was white, slightly soft, and of the size of a nut. Boiling al- 

 cohol extracted from it a little cholesterin. The insoluble por- 

 tion, constituting the greatest portion of the concretion, consist- 

 ed of albumen and phosphate of lime. ( 



2. Pulmonary concretions. It is well known that concretions 

 are occasionally coughed up from the lungs. They are usually 

 enveloped in mucus, and sometimes accompanied by blood, and 

 sometimes not. They may appear without any consumptive 

 tendency. An instance of this is given by Dr Prout. J I ex- 

 amined several of these concretions coughed up by a consump- 

 tive person, and found them composed of phosphate of lime united 

 to a thick membranous substance, which retained the form of the 

 concretion. The same result had been obtained long before by 

 Fourcroy. Dr Henry examined several, and found their con- 

 stitution the same as I had done. Mr Crampton examined one 

 which he assures us was composed of, 



Carbonate of lime, . 82 



Animal matter and water, 18 



100 1| 



One of these concretions examined by Dr Prout consisted chiefly 

 of phosphate of lime, with some carbonate of lime, and an animal 

 matter which retained the size and shape of the concretion after 

 the earthy matter has been removed by an acid.lf 



These concretions, so far as I have seen them, are all small ; 

 sometimes not larger than a pin-head, and hardly ever reaching 

 the size of a pea. They must be deposited in the bronchia? or 

 in the. air-cells of the lungs. 



A concretion examined by Lassaigne, and found in the me- 

 sentery of a bull attacked with phthisis, consisted of phosphate 

 of lime mixed with a little carbonate. ** 



* Phil. Trans. 1797, p. 386. t Ann. de Chim. etde Phys. ix. 327. 



J Annals of Philosophy, xiv. 232. Ann. de Chim. xvi. 91. 



H Phil. Mag. xiii. 287. f Annals of Philosophy, xiv. 233. 



** Ann de Chim. et de Phys. ix. 328. 



