The Splanchnic Preparation
The splanchnic nerves were stimulated in various ways. At first only the left splanchnics in the abdomen were prepared. The nerves, separated from the spinal cord, were placed upon shielded electrodes. The form of electrodes which was found most satisfactory was that illustrated in [Fig. 10]. The instrument was made of a round rod of hard wood, bevelled to a point at one end, and grooved on the two sides. Into the grooves were pressed insulated wires ending in platinum hooks, which projected beyond the bevelled surface. Around the rod was placed an insulating rubber tube which was cut out so as to leave the hooks uncovered when the tube was slipped downward.
Figure 10.—The shielded electrodes used in stimulating the splanchnic nerves. For description see text.
In applying the electrodes the left splanchnic nerves were first freed from their surroundings and tightly ligatured as close as possible to their origin. By means of strong compression the conductivity of the nerves was destroyed central to the ligature. The electrodes were now fixed in place by thrusting the sharp end of the wooden rod into the muscles of the back. This was so done as to bring the platinum hooks a few millimeters above the nerves. With a small seeker the nerves were next gently lifted over the hooks, and then the rubber tube was slipped downward until it came in contact with the body wall. Absorbent cotton was packed about the lower end of the electrodes, to take up any fluid that might appear; and finally the belly wall was closed with spring clips. The rubber tube served to keep the platinum hooks from contact with the muscles of the back and the movable viscera, while still permitting access to the nerves which were to be stimulated. This stimulating apparatus could be quickly applied, and, once in place, needed no further attention. In some of the experiments both splanchnic nerves were stimulated in the thorax. The rubber-covered electrode proved quite as serviceable there as in the abdomen.
The current delivered to the splanchnic nerves was a rapidly interrupted induced current of such strength that no effects of spreading were noticeable. That splanchnic stimulation causes secretion of the adrenal glands has been proved in many different ways which have already been described (see [p. 41]).