56 Transactions of the 



that a great change lias taken place. It has become whiter, more 

 brittle, and very much lighter ; but has not lost its original shape 

 and bulk. This change is owing to the removal of the organic 

 or animal part of the bone ; and what is left is the inorganic 

 or mineral part. If, instead of putting the bone in the fire, you 

 were to digest it with an acid, such as nitric acid (aqua fortis) or 

 hydrochloric acid (spirits of salt), the mineral part would dissolve, 

 and the organic part would be left behind as a gelatinous, flexible 

 mass, still retaining its original shape. 



Hence we find that a bone consists of organic and inorganic 

 matter; and in full-grown bones the proportions of the two would 

 be one-third of the former to two-thirds of the latter. In younger 

 animals the organic exists in greater proportion ; in older ones 

 the reverse is the case. Berzelius gives the following analysis of 

 osseous structure: — 



Animal matter, .... 33 '30 



Phosphate of lime (bone earth), . . 5r04 



Carbonate of lime (chalk), . . 11"30 



Fluoride of calcium (Derbyshire spar), . 2-00 



Magnesia (phosphate, &c.), . . 1*16 



Soda salts, .... 120 



Now the animal matter contains in addition to its gelatine a 

 considerable amount of fat ; and the manufacturer's first care is 

 to get this fat out. For this purpose the bones are simply boiled. 

 The uses of the fat will come under the head of the fat proper, 

 and need not be further mentioned at present. The larger bones 

 are now handed over to the turner, to be manufactured into articles 

 such as have already been spoken of. The smaller ones, together 

 with the dust and chips of the factory, and the pieces punched 

 out of the holes of buttons, &c., are carefully collected, and find 

 several applications. Some parts are digested with steam under 

 a great pressure and made to yield \ip the gelatine, which is 

 the substance from which we derive the jelly for our tables, the 

 wrappings of sweetmeats, glue, size for stiffening straw hats, &c. 

 Another portion, being burnt in close vessels, is converted into 

 animal charcoal (bone-black or ivory-black), and after the removal 

 of the phosphate of lime by means of hydrochloric acid, is exten- 

 sively used as a decolouriser and deodoriser. It is by means of 

 this substance that white sugar is produced, raw sugar being of a 

 dirty-brown colour. From its power of removing foul effluvia, it 

 is an excellent thing for purifying the air from sewers, sick-rooms, 

 &c. One of the most extensive applications of bone still remains 

 to be spoken of — the utilisation of the phosphoric acid. Bone- 

 earth or phosphate of lime forms no less than one-half of the 

 constituents of bone. This phosphate is a compound of three 



