135 On Dr. Mttchlirs Theory 



vated his own cftate, as is common in America. The early 

 part of his Ufe, to the age of feventeen years, was pafTed in 

 the country. In the way he was educated, the implements 

 of hulbandry, and the method of ufing them, were familiar 

 to him : he knew the management of the plough and of the 

 fpade. After the death of his father in 1789, he took pof- 

 feffion of the family-patrimony, and lived on it as a praftical 

 farmer for fcveral years. His experience and opportunities 

 during this feries of agricultural employment, had produced, 

 among other things, a more curious and particular atterrtion 



to MANURES. 



On reviewing his former obfervations, the fubjeft pre- 

 fented itfelf to him under feveral new afpefts. The produc- 

 tion oifeptic acid among the excrements of animals had been 

 long known : the neutralization and fixation of this was, he 

 thought, one of the principal efl'efts wrought by alkalies and 

 lime. Inftead of faying, with the generality of modern ob- 

 fcrvers, that lime was fervjceable by its feptic or putrefying 

 quality, (an opinion for which there is no plaufible founda- 

 tion^) Dr. Mitchill became convinced, its principal effeft 

 was, to combine with feptic acid into calcareous nitre, one 

 of the richeft of manures; and referve this, without volati^ 

 lization or evaporation, fixed upon the foil, to Simulate and 

 feed the plants which grow there. Thus wholefomenefs and 

 fertility were provided for in the fame operation. It fecmed 

 to him alfo, that the deliquefcent property of the feptite of 

 lime enabled it to retain moifture a long time upon the land, 

 and thereby mof^ agreeably fecured the crop from the pinch- 

 ing of drought. 



It was obvious, that if there was much feptic venom (oxy- 

 genated fepton) in any field, yard, or region, and no lime or 

 alkali to neutralize it, epizootic difeafes among cattle might 

 proceed from it, after the manner of epidemic diftempers 

 among the human fpecies. Dews and fogs impregnated 

 with feptic acid, appeared the probable exciting caufes of 

 feveral mortal diforders in ne^t-cattle, fheep, and horfes ; a 



confidcrablo 



