Charley, who has recently come home from college, where he has been studying chemistry, looked at the Deacon, and was evidently puzzled to understand him. Turning to the Doctor, Charley asked modestly if what the Doctor had said in regard to the composition of plant food could not be said of the composition of all our animals and plants.
“Certainly,” replied the Doctor, “all our agricultural plants and all our animals, man included, are composed of these twelve elements, oxygen, hydrogen, carbon, and nitrogen; phosphorus, sulphur, silica, chlorine, potash, soda, magnesia, and lime.”
Charley said something about lime, potash, and soda, not being “elements;” and something about silica and chlorine not being found in animals.
“Yes,” said I, “and he has left out iron, which is an important constituent of all our farm crops and animals.” Neither the Doctor nor the Deacon heard our remarks. The Deacon, who loves an argument, exclaimed: “I thought I knew all about it. You told us that manure was the food of plants, and that the food of plants was composed of the above twelve elements; and now you tell us that man and beast, fruit and flower, grain and grass, root, stem, and branch, all are composed or made up of these same dozen elements. If I ask you what bread is made of, you say it is composed of the dozen elements aforesaid. If I ask what wheat-straw is made of, you answer, the dozen. If I ask what a thistle is made of, you say the dozen. There are a good many milk-weeds in my strawberry patch, and I am glad to know that the milk-weed and the strawberry are both composed of the same dozen elements. Manure is the food of plants, and the food of plants is composed of the above dozen elements, and every plant and animal that we eat is also composed of these same dozen elements, and so I suppose there is no difference between an onion and an omelet, or between bread and milk, or between mangel-wurzel and manure.”
“The difference,” replied the Doctor, “is one of proportion. Mangels and manure are both composed of the same elements. In fact, mangels make good manure, and good manure makes good mangels.”
The Deacon and the Doctor sat down to a game of backgammon, and Charley and I continued the conversation more seriously.