116 ELEMENTARY PHYSIOLOOxY less. 



the fibrinogen of the platsma and the fibrin fills up the 

 wound and assuages the bleeding. 



10. The Quantity and Distribution of Blood in the 

 Body. — The total quantity of blood contained in the body 

 varies at different times, and the precise ascertainment 

 of its amount is very dithcult. It may probably be 

 estimated, on the average, at not less than one-twentieth 

 or about 5 per cent, of the weight of the body. 



Its distribution may be stated in round numbers as 

 follows : — 



One quarter, in the heart, lungs and large blood 

 vessels. 



One quarter, in the liver. 



One quarter, in tlie skeletal muscles. 



One ([uarter, in the other organs of the body. 



11. The Functions of the Blood.— The function of 

 the blood is to supply nouiislnnent to, and tiike away 

 waste matters from, all parts of the body. All the 

 various tissues may be said to live on the blood. From 

 it they obtain all the matters they need, and to it they 

 return all the waste material for which they have no 

 longer any use. It is absolutely e.ssential to the life of 

 every part of the body that it should be in such relation 

 with a current of blood, that matters can pass freely from 

 the blood to it, and from it to the blood, by transudation 

 tluough the walls of the vessels in which the blood is 

 contained. And this vivifying infiuence depends upon 

 the corpuscles of the blood. The proof of these state- 

 ments lies in the following experiments : — If the vessels 

 of a limb of a living animal be tied in such a manner as to 

 cut off the supply of blood from tlie limb, without affect- 

 ing it in any other way, all the symptoms of death will 

 set in. The limb will grow pale and cold, it will lose its 

 sensibility, and volition will no longer have power over it ; 

 it will stiffen, and eventually mortify and decompose. 



But, if tlie ligatures be removed before the death 

 stiffening has become thoroughly established and the 



