OSTEOLOGY IS 



subjecting the bone to strong heat in an open fire 

 where the air can have free access, until all the organic 

 material is consumed, when the earthy parts will be 

 found to be brittle, preserving the original shape of the 

 bone. 



The organic constituents of bone make up one-third, 

 or 33.3 per cent., of the whole; the inorganic matter, two- 

 thirds, or 66.7 per cent. For the convenience of the 

 nurse we append the following table of analysis by Berze- 

 lius (from Wilson) : 



/Cartilage 3 2 - J 7 



Organic matter : < . , , . T ^ 



I Blood-vessels I-I3 



r Phosphate of lime 51.04 



1' Carbonate of lime H-3<> 



Fluoride of calcium 2.00 



Phosphate of magnesia 1. 1 6 



Soda and chlorid of sodium . . . 1.20 



IOO.OO 



Some difference exists in the proportion of the two 

 constituents of bone at different periods of life. Thus 

 in a child the animal matter predominates, whereas in 

 the aged the bones contain a larger proportion of earthy 

 matter, the animal matter being deficient in quantity and 

 of impaired quality. Hence in children it is not uncom- 

 mon to find, after an injury, that the bones become bent 

 or partially broken a condition known as greenstick 

 fracture whereas in old persons the bones are more brittle 

 and fracture thus takes place more readily. Many of 

 the diseases, also, to which bones are liable are due to a 

 disproportion between the two constituents of bone. 

 Thus in the disease known as rickets, so common among 

 children of the poor, the bones become bent or curved, 

 either from the superincumbent weight of the body or 

 under the action of certain muscles. This is due to some 

 defect of nutrition by which bones are deprived of their 



