166 USES OF BLOOD 



Corpuscles were first seen in the blood of a 

 frog by Swammerdam in 1658, by Malpighi 

 in that of the hedgehog in 1661, and by 

 Leeuwenhoek in the blood of man in 1673. 



Uses of Blood. 



(1) < To be a medium for the reception 

 and storing of matter (food, drink, and oxy- 

 gen) from the outer world, and for its convey- 

 ance to all parts of the body. 



(2) ' To be a source whence the various 

 tissues of the body may take the materials 

 necessary for their nutrition and maintenance, 

 and whence the secreting organs may take 

 the constituents of their various secretions. 



(3) 'To be a storehouse of potential energy, 

 by the expenditure of which the heat of 

 the body may be maintained ; and by cor- 

 relation, vital and other force may be 

 manifested. 



(4) ' To be a medium for the reception of 

 refuse matters from all the tissues, and for 

 their conveyance to those organs whose func- 



