Report of the Royal Commission on the practice of subjecting live animals to experiments for scientific purposes : with minutes of evidence and appendix.

Great Britain. Royal Commission on Vivisection

Date:: 1876

Credit: Report of the Royal Commission on the practice of subjecting live animals to experiments for scientific purposes : with minutes of evidence and appendix. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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$opening a thin-hladed knife is introduced in the middle plane with its edge outwards, by which the medulla is divided, first on one side, then on the other. . . . The currents direct application of the electrodes to the sensory nerves, Init strong when it is intended to excite their cutaneous or mucous endings. The periods of excitation should always be very short. The experiment may be varied as follows :— A frog having been carefully curarized the points of the excitor are placed upon the tongue, the mouth being kept open for the purpose. Page 243.—A frog having been curarized the integu- ment is divided along the outer and posterior aspect of the thigh in a line which corresponds in direction with the slender biceps muscle, or rather with the groove between the muscular mass which covers the front of the femur (triceps femoris) and the bulky semi-membranosus. The sciatic nerve, accompanied by the sciatic artery and vein, lies immediately underneath the biceps, between it and the semi-membranosus. In order to separate it from the vessels it is best to bring it into view by raising the biceps on a blunt hook. ..... The nerve is divided a little above the knee and the central end laid on the copper points. Page 245.—The animal having been curarized the ap- paratus for artificial respiration is connected with the trachea. .... The great auricular nerve is thin carefully exposed, separated from the sur- rounding parts with the aid of two pairs of blunt forceps, and divided. . . . . If care is taken neither to prolong the excitation unduly, nor to use too strong currents, the re-action may be witnessed a great number of times in the same animal. Page 265.—The heart of a frog having been exposed in the usual way, a stout glass rod is introduced into the msophagus. All the other organs may now be removed in the manner directed in § 63, care being taken to avoid interfering with the venae cavae. • Page 26f).—A frog having been klightly curarized. the sternum is then divided in the middle line, and the two halves of the wall of the chest drawn to either side, so as to ex])ose the pericardium and lungs, while a stout glass rod is passed down the aesophagus. Page 271.—The preliminary steps of the experiment are those described in § 34. Loose ligatures having been' ])laced round both vagi, and a kymographic observation made to determine the normal arterial pressure and frequency of the pulse, both nerves are divided simul- taneously. [Of a dog.] .... The contractions of the heart become so frequent that the oscillations can no longer be followed by the eye, all that can be distinguished being a vibratile movement of the column. On exciting the peripheral end of either vagus the same effects are produced as in the rabbit. Page 272.—A frog is secured in the supine position. The pleuro-peritonEcal cavity is then opened, and the intestines and other viscera are removed, great care being taken not to injure the mesentery or the vessels and nerves which it contains. Page 273.—To show this a frog is secured on its back, the pleuro-peritonseal cavity opened, and the heart exposed as before. The surface of the intestine is then smartly tapped. . . . . . . If the ganglionic cord is then divided on each side opposite the junction of the two aortee, and the experiment repeated, no effect is produced. Another frog is prepared in the same way, ivith the exception that both vagi are divided. . ‘ . . . The same thing happens if, instead of didding the vagi, the cord is divided immediately below the medulla. ...... In a rabbit the trachea is connected ivith the apparatus for artificial respiration, and the vagi are e.xposed in the neck. Thereupon the spinal cord is divided imme- diately below the medulla oblongata. . In the dog, section of the cord generally diminishes the frequency of the pulse. There is no such effect in the rabbit. Page 278.—In a curarized rabbit, in which artificial respiration is maintained in the usual way, an incision is made in the middle line, extending from the upper third of the sternum to the upper end of the trachea. The external jugular vein of one side is then brought into view, tied in two places, and divided between the ligatures. The sterno- mastoid muscle is also divided between ligatures; a strong threaded aneurism needle is thrust under the sterno- clavicular ligament, and the upper fibres of the pectoral muscles; these with the ligament are divided between . The superficial parts having been e.xposed by two lines of incision, one of which is in the middle line, while the other extends from it on either side jugular vein having been divided , between ligatures, the next step is to find the pneumogastric nerve at the upper part of the wound, and free it from the surrounding tissues. . . . . .To find it, the most certain method is to seek for the trunk of the sympathetic in the upper part of the space, where it lies concealed behind the carotid artery, and then to trace it down to the ganglion. All this having been accomplished without bleeding, there is no difficulty in passing a ligature round the ganglion, so that at any desired moment it may be extirpated. ..... Both ganglia having been thus prepared with as little loss of time as possible, the sympathetic and vagus are divided. . The medulla oblongata is then divided. Page 285.—Two frogs having been slightly curarized are prepared thus : the heart having been exposed lege artis, a small opening is made in the skin in the occipital region. In one of the frogs the brain and spinal cord are com- pletely destroyed by passing a needle upwards and down- wards from the occipital region, and then both are hung vertically on a board, side by side, looking in the same direction. [Sensibility is retained in the other.] .... The discharge of sanguineous liquid goes on for one or two hours, and if during the progress of the experiment, the vasomotor centre is stimulated reflexly by exciting a sensory nerve-or the surface of the skin, it is seen that the rate of flow is at once augmented, but becomes less after the cessation of the excitation than it was before. Page 289.—This may be demonstrated graphically by puncturing the anterior wall of the visceral cavity, and introducing through the puncture a cannula in such a way that it communicates with the cavity of one lung. Page 2.93.—A rabbit having been secured on the rabbit support, the skin is perforated with a scalpel close to the left edge of the middle of the sternum. This having been done, the point of the tube is easily passed into the right pleura by. pushing it in a horizontal direction behind the sternum, with its point against the posterior {i.e., as the animal is placed the under) surface of the thoracic wall. Page 297.—The student must avail himself of the e.xcessive and infrequent respirations of animals in which both vagi have been divided. Page 298.—The best view of the movements is obtained by dividing the hyothyroid membrane. The skin having been carefully divided in the middle line, lege artis, the membrane must be exposed with the aid of two pairs of forceps. Page 306.—A ligature is passed round each nerve a little below the cricoid cartilage. Page 308.—Rabbits in which both vagi have been divided commonly die before the end of the first day. Dogs live longer, often two or three days. Page 309.—By far the best method is to introduce into the peritonaeal cavity, by means of a small opening in the linea alba, close to the ensiform cartilage, a small flat bag of india-rubber of such size that it can be conveniently slipped between the diaphragm and liver. Page 312.—Excitation of the superior laryngeal nerve.— The experimental in^-estigation of the superior laryngeal is much more difficult than that of the trunk of the vagus, partly because the nerve is difficult to reach and runs a short course, partly because it is very slender. To expose it in the rabbit, an incision should be made extending from the side of the trachea at the level of its first and second rings to the hollow between the angle of the jaw and the larynx. After severing the skin in the usual way, the fascia which extends forwards from the edge of the sterno- mastoid muscle must be carefully broken through with the aid of two pairs of dissecting forceps, so as to expose the parts seen in fig. 227. The space is divided into two by the artery, the direction of which coincides exactly with that of the original incision. Near its lower end the artery gives off its thyroid branch. At the top the space is limited by the tendon of the stylohyoid muscle, and the posterior cornu of the hyoid bone. Immediately below the muscle is the trunk of the ninth nerve which arches forwards towards the tongue. The descending branch of that nerve passes downwards and forwards to reach the muscles which cover the front of the trachea, giving communicating branches to the cervical plexus, and a branch which arches forwards over the artery to gain the muscles which draw the larynx' upwards. Before proceeding to expose the$