54 WISCONSIN STATE AGRICULTURAL SOCIETY. 
that wheat grows and matures its grain when planted in isolated 
pounded granite, getting all its elements from the water and the 
air and the granite. It is not so well known however, that the 
leaves of trees decompose and destroy noxious malaria. When 
planted around stagnant pools and sluggish streams, which 
were destructive of life, they have rendered them healthful and 
innoxious. 
The influence of air upon animal life is more apparent. Any 
one may make a simple experiment. Wax a table or board, 
and inclose a mouse in a glass, and make it air tight, by means 
of the waxed surface. The mouse at first breathes freely— 
then more feebly—then dies ! The reason is, that the oxygen, 
the vital part of the air, is exhausted, then life ceases ; as a 
taper expires for want of oil. The dark blood in the lungs 
(venous) comes in contact with the air inhaled, parts with a 
portion of its carbon, and then grows lighter ; and passing 
through the left auricle of the heart, becomes arterial blood ; 
passing through the arteries and the capillary system , it changes 
into nutrition, in part ; is thrown off through the perspiratory 
vessels of the skin, in part ; and the balance is returned 
through the veins into the right auricle of the heart, which by 
contraction and a valvular structure, throws it again into the 
lungs ; where once more it becomes exposed to the air, and is 
made vital again. When the venous blood fails to throw off its 
carbon, and absorb oxygen, the blood returns unchanged into 
the arterial circulation, and produces paralysis of the heart, and 
arterial ffction, and death ensues ! 
Now with all these facts every scholar should be familiar ; 
yet we find graduates of colleges and men in high places, utterly 
ignoring them. I have seen fifty or sixty men, women and 
children caged in a railroad car, where the air-lets were sham, 
being closed up with tin ! The consequence was that the stove 
and the lungs of so many human beings exhausted the oxygen 
ef the air faster than it could creep in at the.cracks in the floor 
and walls, and all became deadly sick, by partial suffocation ! 
What cared these men for the lives of their passengers, provided' 
