THE use of a capacitance meter to measure the amount1, wet and dry matter content2 and water content3 of pasture herbage has been described previously. As similar data are of interest in farm animals4,5, an apparatus was designed by two of us (D.S.M.P. and G. de la M. N.) to measure the capacitance and resistance of live lambs. The instrument essentially consists of two parallel plates of aluminium foil 3 ft. square backing on bakelite sheets 12 in. apart. Capacitance and resistance measurements were taken on a Wayne Kerr radio frequency bridge B601 at a frequency of 5 Mc/s. The plate nearer the operator was earthed and he had to keep a constant position while readings were being taken on lambs. A background reading was taken before and after each lamb recording and the mean of the two background readings was subtracted from the measurement for each lamb to give those reported here. Duplicate runs were made on each series of lambs and the mean of the two observations has been used in all calculations.