PHILOSOPHY OF EXERCISE. 875 



being retained, and the oxygen returned to the 

 air in that state of purity required for the respi- 

 ration of animals. In a recent Paper read before 

 the Academy of Sciences, by M. Leblanc, he 

 states, that in the great Lecture room of the 

 Sorbonne, (after being filled Ih. 30m.) and in one 

 of the Parisian churches, the amount of carbonic 

 acid was about one per cent. ; while in Hospi- 

 tal wards it was from three to eight times more 

 than in the open air. But in the closed green- 

 houses of the Jardin des Plantes, the air was 

 pure as out of doors. 



See all things with each other blending, 

 Each to all its being lending, 

 All on each in turn depending 

 While everywhere diffused is harmony unending. 



(Faustus, by Goethe.) 



It was long ago observed by Hippocrates, that 

 nothing is more essential to good health, than a 

 just proportion of aliment and exercise, that 

 men require more food during winter than sum- 

 mer, because the inward heat of the body is 

 stronger during winter, and that as it is the 

 tendency of exercise to diminish the substance of 

 the body, it is the object of aliment to replace 

 what has been lost. Yet it must be admitted, 



lignin, starch, sugar, acids, and especially oils or resins, water 

 is decomposed, its hydrogen being assimilated, and its oxygen 

 returned to the air. (Vol. i. pp. 1722.) 



