useful rheophore; and by using the edge it may be Different kinds of Rheophores. made to answer in the majority of cases for fig. 32. It also has the advantage over the sponge of allowing firm pressure to be made without the inconvenience of water being squeezed out. a, fig. 29,

shows the usual method of connecting the conducting cord with the rheophore, which is seen in situ, received into the screw socket of the rheophore in a'. The cord is very apt to get frayed where it passes through the eyelet hole, which spoils it at

Different kinds once.

That the wire which has been previously of Rheophores. recommended is not open to this objection is not the least of its advantages. Figs. 31 and 32 are other varieties of rheophore, fitted chiefly for application to very small muscles, such as the interossei, and some of those of the face. Fig. 33 shows Duchenne's method

Method of

holding Rheophores.

Method of holding the Sponge-holders in a single hand.

of holding two rheophores. The application is being made to the muscles of the hypothenar eminence with one hand, while the other hand is employed about the instrument. In fig. 34 the conical rheophores are in like manner applied to the face. As it is requisite to administer to a muscle a dose of electricity proportionate to its degree of excitability, the operator should whenever possible have

observed in

one hand at liberty. In direct electrization the rheophores must always be applied over the fleshy body of the muscle and not over its tendons, and Rule to be in order to electrize it completely they should cover the Direct Muscuwhole of its surface, and when they are not large enough tion. to do this, they must be applied in succession to all points of its surface. The

FIG. 34.

thicker the substance of the
muscle the more intense must
be the current, because a
weak current will only pro-
duce excitation of the super-
ficial layers. It is very ne-
cessary in practice not to
lose sight for a moment
of this fundamental axiom,
which one is very apt to
do, and so unequally to
electrize the muscle; and
it is a good rule to pro-
menade, as it were, the
two rheophores, held as in
fig. 31 or fig. 33, in lines
along and across the muscle or group of muscles;
keeping them stationary on every point of the muscle
for about thirty seconds, and letting the entire ap-
plication vary from five to fifteen minutes, according
to therapeutic requirements. In direct electrization
with the interrupted voltaic current it is more usual

Duchenne's method of holding conical
rheophores.

lar Electriza

Indirect Muscular Electri

zation.

to maintain one rheophore stationary, and to glide the other in lines from the first. As a rule the positive electrode is the stationary, and the negative the moveable one, but this order can be reversed if necessary.

INDIRECT MUSCULAR ELECTRIZATION.

When muscular contraction is produced by acting upon the special nerve trunk and branches instead of by placing the rheophores upon the muscle itself, the procedure is termed indirect muscular electrization. For its successful practice a detailed knowledge of anatomical relations is necessary, especially of the position of the muscles and of their nerves with regard to one another, to the sensitive nerves and to the surface of the body. It is common to find variations in the course of the nerves, and in the mode of their distribution among the muscles, so that the points most suitable for their excitation can only be pointed out approximately.

It is convenient to place a broad conductor, such as a sponge contained in a cylinder (fig. 28), upon some little sensitive part of the body, such as the sternum, and to apply a fine-pointed conductor, such as the conical rheophore (fig. 32) to the most superficial point of the nerve it is desired to act upon.

The Head.

The trunk of the facial nerve may be excited from the external auditory meatus by pressing a

Nerve.

Stylo-hyoid

thin electrode against its lower wall. Energetic The Facial contractions will be produced in all the muscles that the nerve supplies. With less pain in thin persons it may be found immediately after it leaves the stylo-mastoid foramen. Press the rheophore strongly, just below the concha, between the mastoid and condyloid processes. The branches Branches to from the facial to the stylo-hyoid and digastric and Digastric. muscles may be excited in thin men by pressing the electrode deeply behind the condyloid process of the lower jaw. Their contraction is shown by movements of the os hyoides outwards, backwards, and upwards. In the parotid gland the single large branches of the facial are easily found, and produce contraction in definite groups of muscles corresponding to the ordinary divisions of the nerve; those branches which leave the parotid, and rest more or less closely on the bone, are easily excited, but not those that are imbedded in soft parts, especially the buccal branches. The frontal Branch to muscle may be thrown into contraction from be- Muscle. yond its own limits, since the branch of the facial by which it is supplied, before dividing for its final distribution, courses for some distance from the temple to the zygoma. The orbicularis palpebra- Branch to rum may be excited either upon the zygoma or Palpebrarum. beyond it towards the parotid gland; close to the orbital margin the nerve commonly divides into a superior and inferior branch supplying the upper

Frontal

Orbicularis