... Shake up a little flour with ether in a test tube, with a tight-fitting cork. Allow the mixture to stand for an hour, shaking it from time to time. Filter off the ether, and place some of it on a perfectly clean watch glass. Allow the ether to evaporate, when a greasy stain will be left, thus showing the presence of fats ... — A Practical Physiology • Albert F. Blaisdell