In order to exercise the muscles best and with the least amount of pain and annoyance, we make use of an induction current, with interruptions as slow as one in every two to five seconds, a rate readily obtained in properly-constructed batteries.[24] This plan is sure to give painless exercise, but it is less rapid and less complete as to the quality of the exercise caused than the movements evolved by very rapid interruptions. These, in the hands of a clever operator who knows his anatomy well, are therefore, on the whole, more satisfactory, but they require some experience to manage them so as not to shock and disgust the patient by inflicting needless pain. The poles, covered with absorbent cotton well wetted with salt water, which may be readily changed, so as not to use the same material more than once, are placed on each muscle in turn, and kept about four inches apart. They are moved fast enough to allow of the muscles being well contracted, which is easily managed, and with sufficient speed, if the assistant be thoroughly acquainted with the points of Ziemssen. The smaller electrode should cover the motor-point and the larger be used upon an indifferent area. After the legs are treated, the muscles of the belly and back and loins are gone over systematically, and finally those of the chest and arms. The face and neck are neglected. About forty minutes to an hour are needed; but at first a less time is employed. The general result is to exercise in turn all the external muscles.[25] No such obvious and visible results are seen as we observe after massage, but the thermal changes are much more constant and remarkable, and show at least that we are not dealing with an agent which merely amuses the patient or acts alone through some mysterious influence on the mental status. A half-hour's treatment of the muscles commonly gives rise to a marked elevation of temperature, which fades away within an hour or two. This effect is, like that from massage, most notable in persons liable to fever from some organic trouble, and it varies as to its degree in individuals who have no such disease. The first case, Miss B., æt. 20, is an example of tubercular disease of the apex of the right lung. She had a morning temperature of 98-1/2° to 99-1/2°, and an evening temperature of 100° to 102°. Electricity was used about 11 o'clock daily, with these results: Before Electricity. After Electricity. November 25 99 99-3/5 " 27 97-3/5 100 " 28 98 99 " 29 98-4/5 99-4/5 December 2 100-1/5 101-3/5 " 4 99-1/5 100-1/5 " 5 99-2/5 99-1/5