Lacteals, in physiology, are the absorbing vessels of the mesen-try, and consist of certain small tubes, situated in the intestines; whence they convey the chyle, or that milky fluid which is generated from the food in the first passages, into the common reservatory, or the mass of the blood. They are furnished with an incalculable number of valves, which prevent the return of the chyle into the stomach : in their passage through a number of glands, the nature of the last-mentioned fluid is considerably altered, and prepared for its assimilation with the blood.