The reactions of experimental animals and of human beings to stimulation with the galvanic current have been investigated since early in the nineteenth century. Not only the reactions of normal subjects, but the reactions of animals and human beings with all types of experimentally produced and spontaneous lesions have been the subject of numerous investigations. Experiments on the latter group were carried out in an attempt to establish galvanic stimulation as a clinical procedure which might replace, or at least serve as an adjunct to, performance of the caloric and the rotation test for vestibular function.Nystagmus, postural reactions, such as turning and rotation of the head, subjective vertigo and a tendency to fall have all been observed as a result of galvanic stimulation of the ears. The nystagmus has received more attention than the other reactions, because of an attempt of the investigators to correlate the galvanic reaction with the reactions elicited by caloric and rotatory stimulation. The direction of the postural reaction in normal subjects has been established as toward the anode; i. e., if the anode was in contact with the right ear, the head was turned toward that side and rotated so that the right ear was lowered. There was also a tendency for the subject to fall to the right.Ritter 1 was apparently the first author to investigate the effects of galvanic current in the production of vertigo. He was particularly interested in the amounts of current necessary to elicit responses of various kinds in persons of different age and sex.

No abstract

In two previous communications 1 we have discussed the galvanic reaction in normal and in unilaterally and bilaterally labyrinthectomized guinea pigs. The present study has to do with the galvanic reaction in guinea pigs in which the eighth nerve on one side was destroyed.Dohlman 2 experimented with the galvanic reaction of animals in which the vestibular nerves were sectioned intracranially or in which the vestibular ganglion had been removed. He concluded that elicitation of galvanic nystagmus is dependent on integrity of the cells in the vestibular ganglion and their central connections. This conclusion is in agreement with that of Blau,3 who found in cats, guinea pigs and an ape that nystagmus could still be elicited with the galvanic current when the labyrinth was completely destroyed. He proved by microscopic examination of the temporal bone that Scarpa's ganglion cells and the eighth nerve were still intact in these animals. Malassez,4 after conducting examinations of deaf-mutes, concluded that the integrity of the semicircular canals is essential for postrotatory nystagmus but that the galvanic reaction can be obtained if a part at least of the vestibular nerve is still intact. Northington and Barrera,3 working with monkeys,