Chap, xvi.] PHYSIOLOGICAL OFFICE OF KESPIRATIOIT. 255 



plasmas, certain substances destined afterwards to play more or 

 less important parts in the different functions. Thus it is that 

 we have to speak of excretion and secretion. 



NOTE. 



A litre is about a quart English. A kilogram/me is a thousand grammes. 

 According to the new system of weights and measures introduced into France 

 at the Eevolution, ded as a prefix means tenth ; centi, hundredth ; Tn/iUi, 

 thousandth, when the princi^ unit is progressively fractionised : — deca as a 

 prefix means tenth ; heoto, hundredth ; kilo, thousandth, when the principal unit 

 is progressively augmented or multiplied. Thus millimHre is the thousandth 

 part of a mitre; hectogramme a hundred grammes, and so on. In Professor 

 Koscoe's Lessons in Elementwry Chemistry a comparison of the French 

 metrical with the common measures is given, — Translator. 



