Faradisation of nerve trunk is resorted to mainly for inducing
contractions in groups of muscles; or of muscles not to be excited
directly. We thus faradise the phrenic and posterior thoracic
nerves in the neck for stimulating the action of the diaphragm and
serratus magnus. The method to be used here is that described as



1 62 GENERAL ELECTRISATION.
the unipolar (p. 147), one electrode being placed at a distant part of
the body, the other on the motor point.
Faradisation of special organs will be found described in the
special part under the different diseases where it is applicable.
The various forms of electrodes necessary for this purpose are
shown in the chapter on apparatus, (p. 92).
GENERAL ELECTRISATION.
Under this head we include central galvanisation, general fara-
disation, and electric baths.
Central galvanisation consists in bringing the whole cerebro-
spinal axis under the influence of the current. The negative pole
being held stationary over the pit of the stomach or the sacrum, the
positive pole is held first upon the forehead and vertex, then along
the course of the sympathetic and pneumogastric in the neck, lastly,
upon the cervical, dorsal, and lumbar regions of the cord succes-
sively. Here, as usual, a very caretul graduation of current
strength is needed during the application to the head and neck.
Strong currents may usually be applied to the spine without fear.
The duration may extend to 2 minutes to the head, 4 to the neck, and
10 to the spine. Central galvanisation is indicated in cases of
general nervous depression, of nervous insomnia, etc., and is useful
as an adjunct to local modes of treatment.
