INORGANIC CONSTITUENTS. 27 



the liquids of the body attain a certain degree of concentra- 

 tion, or when the solids have lost a part of their neces- 

 sary proportion of water, thirst is induced. Thirst is the 

 indication of water being required by the system. The 

 quantity of water needed varies largely in the organization of 

 different animals and plants. It always constitutes a very 

 large part of organic texture. This may be seen by taking a 

 piece of tendon, which is even materially altered in its appear- 

 ance by losing or regaining moisture. It is tough, pliable, 

 bulky, heavy, white, and opaque in its natural state. It be- 

 comes hard, transparent, light, and of a yellowish or brownish 

 colour if dried, and so perfectly does this white fibrous tissue 

 preserve its structural peculiarities in the dried state, that if 

 damped a century after it was first deprived of moisture, it 

 acquires again the bright silvery look of ligament or tendon. 

 I was struck by this in recently washing the ligaments of 

 Eclipse's skeleton. The quantity of water, as compared with 

 solid matter in animal tissue, is sometimes so great, that Owen 

 found a jelly-fish, weighing 2 Ibs., contain only 16 grains of 

 solid matter. It usually exists in the higher animals in the 

 enormous proportion of 70 per cent. 



Eobin and Verdeil found in the different solids and fluids 

 the following proportions of water : 



Quantity of Water in 1000 parts in 



Epidermis . . 37 



Teeth . . .100 



Bones . . .130 



Cartilage . .550 



Muscle . . .750 



Ligament . . . 768 



Brain . . .789 



Blood . . .795 



Synovial fluid . . 805 



Bile .... 880 

 Milk .... 887 

 Pancreatic juice . . 900 

 Urine . . .936 

 Lymph . . .960 

 Gastric juice . . 975 

 Perspiration . . 986 

 Saliva 995 



