MODERN IDEAS OF SANITARY ECONOMY. 



61 



" Excellent medical men and philosophers have believed it 

 to arise from the inclemency of the weather, that is, from the 

 too great heat, cold, moisture, or dryness. 



" So also every thing grows better where there is no excess 

 of heat, cold, moisture, or dryness. But with any excess of 

 these the force of the disease increases, and man and beast are 

 attacked by pestilence. Whence it happens that inhabitants 

 of moist and marshy places are liable to be attacked by this 

 evil. But heat is especially destructive, whence some say 

 they call the sun Apollo (as anoWwra ra $a>a.) But as the 

 immoderate heat of the sun destroys all living things, so also 

 its temperate heat removes all diseases, whence the Greeks 

 called Apollo AXe^iKUKOPt the remover of evils, a name also 

 given to Hercules. 



** Some say that waters, vitiated and corrupted by foetid 

 matter, destroy health and prepare pestilence. For Aristotle 

 says that the changes of water are very important, and Lucre- 

 tius agrees to it in the line-^ 



* Nonne vides etiam cceli novitate et aquarum.' 



" Some are greatly tried by being at a distance from 

 their homes ; and Vitruvius writes, that grave and pestilent 

 humors escape from the Pontine marshes. And, as Seneca 

 says, noxious and pestilent waters lie in the depths of the 

 earth, containing nothing but what is pestiferous and un- 

 wholesome to our bodies; these, after an earthquake, come 

 out, and when people drink them, they cause pestilence. 



" Some say that pestilence arises from the noxious evapo- 

 ration of the earth, and that the earth is constantly giving out 

 vapours ; and certainly it is clear that the earth is not without 

 a spirit, which it pours out abundantly for the growth of all 

 vegetation. 



" Avicenna also says that the corruption of the air is raised 

 from the earth. Silius, alsO;, in describing a pestilence, says 

 that the vapour of the earth is pestilential, in the verse — 

 ' Atque ater picea vapor expirabat in Etbra.' 



