Feeding stalls of the Lehmann type, which are generally employed when sheep are used for digestibility trials, are useful if wethers act as experimental animals. The wether, however, is not an ideal subject for investigations in which it is desired to estimate the utilisation of individual nutriments, for the portion of the ration which is retained usually constitutes but a small part of that ingested and, in consequence, when attempts are made to draw up a true balance considerable errors are often encountered through the difficulty of ascertaining the total volume of urine excreted during the feeding period. This uncertainty may be overcome, for if the ewe is used a catheter may be passed into the bladder and the urine completely drained at the will of the experimenter.