“ After the crop has been removed these are allowed to harden or become woody, and then farm-yard manure is scattered over the field and ploughed in. In this way the stolons are divided into numerous pieces, and covered with soil before the frost sets in. If the autumn is wet they are liable to become sodden, and rot, and the next crop fails. In the spring the fields are dressed with Peruvian guano. In new ground the peppermint requires hand-weeding two or three times, as the hoe cannot be used without injury to the plants. ”

“ Oil of peppermint is often adulterated with a third part of rectified spirit, which may be detected by the milkiness produced when the oil is agitated with water. Oil of rosemary and rectified oil of turpentine are sometimes used for the same purpose. If the oil contains turpentine it will explode with iodine. If quite pure it dissolves in its own weight ”

“ Moist heavy weather in August is apt to cause the foliage to drop off and leave the stems almost bare. In these circumstances rust (Puccinia menthae) also is liable to attack the plants. This is prevented to a certain extent by a rope being drawn across the plants, by two men walking in the furrows, so as to remove excessive moisture. ”

“ In America the oil is liable to be injured in flavour by aromatic weeds which grow freely among the crop, the n1ost troublesome of these being Erigeron canadense, and Erechthites hieracifolia. When pure the oil is nearly colourless and has an agreeable odour and powerful aromatic taste, followed by a sensation of cold when air is drawn into the mouth. ”