18 MASSACHUSETTS AGRICULTURE. 



will insure you less dysentery, less cholera infantum and 

 majorum, fewer fevers, and, in fine, better bowels the year 

 round. 



A most reliable and sure poison for farmers is the miastna, 

 or poiso7ious vajjor, generated in the refuse ^natter about the 

 house and the barn. And this is a more common and destruc- 

 tive poison than either of the others just mentioned. And 

 most of our fevers are caused by the noxious exhalations, or 

 germs, rising from decaying organic matter. Till within a 

 few years, the air contained in the upper few feet of soil has 

 never been brought to notice. And this does not mean sim- 

 ply that air is cold and damp on the ground, but that the 

 upper few feet of soil — say six — contains much carbonic acid 

 and other poisonous gases. A writer who is probably the 

 first living authority on this subject, says : "A few feet under 

 the surface there is already as much carbonic acid as there is in 

 the worst ventilated human dwellings." Now those gases are 

 not only out in the fields, and at a distance from the house, 

 but they may be, and are, more or less under our dwellings, 

 their abundance depending on the nature of the soil and the 

 proximity of their source. And though there may be no 

 production of them in our own yards, yet these exhalations 

 may travel a long distance underground. In other words, 

 there are currents and winds underground as well as above it. 

 One proof of this is seen in the fact that in cities and large 

 towns where coal gas is burned for illumination, it may often 

 be perceived in a cellar where the pij^es are not laid, and even 

 where there is not a main for a long distance. Another proof 

 is found in frozen wells, which are not uncommon. How far 

 underground these gases may travel and enter our cellars, 

 like demons of destruction, research has not yet informed us, 

 since so much depends on location, the nature of the soil, and 

 the prevalent winds above the ground ; but the fact remains, 

 that deadly gases do course rapidly through the soil, making 

 what Pettenkofer calls "ground air," and these gases do come 

 up under our dwellings, and produce certain diseases. These 

 gases travel much more slowly in cold than in warm weather, 

 since sunlight and cultivation render the soil porous and easily 

 permeable by them. And hence we see why fall fevers pre- 



