In 1845, Mr. L. M. Norton, of Goshen, Conn., discovered that the acid in curd could be gauged by stringing threads from a heated iron. He kept the discovery a secret for a long time but at last divulged it. To supply yourself with a handy instrument for testing acid, take a three-quarter inch bar of iron a foot long and set one end into a ferrule on a wooden handle. It can then be conveniently handled without burning the fingers. Heat the metal a little hotter than desired and then thrust for a moment into a bucket of water, to thoroughly clean the surface. Holding it in the left hand, take a piece of curd squeezed dry of whey and press against the iron. If it does not adhere at all, the curd is perfectly sweet, no matter how it may smell to you. If it clings slightly, you may be assured that acid is beginning to develop, so keep close watch of it. Curd ought never to string out threads more than one-fourth of an inch long before whey is drawn, and oftentimes less is desirable. Have the iron at just the right temperature or you cannot make an accurate test. A right temperature implies that the iron is so hot that the curd will fry around the edges when pressed against it, but not so hot that it will scorch over. Tainted and floating curds will often string threads six inches and more in length, and then not be fitted to grind and salt. As soon as acid has overcome the gaseous condition of such curd so that the inflation will subside, it is ready to grind, but not before. Cheese makers should not be afraid of souring and airing such curd too much. MILK. In the manufacture of cheese the constituents of milk demand our first attention, as we cannot intelligently study a subject without investigating its primary principles. Cow’s milk contains: Water 864 parts. Nitrogenous matter (caseine and albumen) 43 ” Sugar of milk 52 ” Fat 37 ” Mineral salts 4 ” ————— 1,000