“Let me refer to what has been done by Dr. Roy in 1880, partly in the Physiological Laboratory at Cambridge, and partly in the Leipsic Philological Institute, the experiments being carried out on rabbits, cats, and dogs. The animal was placed under curare, artificial respiration was used, that is to say, a tube was pushed down the animal’s windpipe, and worked by an engine in regular puffs in order to keep the blood oxygenated. Then the back, skull, chest, and abdomen were opened. I don’t suppose these were always opened in one animal, as in many cases the animal would have died. No doubt sometimes part of the experiment took place on one, and sometimes on another. The various organs were dissected out. The principal nerves such as the sciatic nerve and so on, were tied in two places and cut. This lasted for many hours. It is stated the animal was under the influence of anæsthetics, but the use of curare is admitted. In the most scientific opinion, when curare is used, it neutralizes the use of the anæsthetic. I feel myself at a great disadvantage in treating of these matters as compared with the gentlemen beside me; but if I am making a mistake, I trust I may be corrected. In this instance, however, I believe I am right. Curare creates paralysis, it paralyses the muscles and prevents the animal resisting or showing the symptoms by which alone the existence of anæsthesia can be tested.”—Mr. Reid’s Speech in House of Commons, April 4th, 1883.
“It was first sought to obtain information upon this subject by investigating the manner and extent to which the action of the heart is affected by obstruction of the renal arteries and the other large branches of the aorta; the facts obtained by taking this line of inquiry were not however of a kind fitted to throw light upon the problem which it was specially desired to solve. It soon became evident that an investigation of the manner in which the renal secretion and circulation are nominally regulated, and the relation which these bear to the regulating mechanism of the systemic circulation, would be best fitted to supply information of the kind required. The method employed, was to record graphically the changes in volume of one or both kidneys, while at the same time the changes in the blood-pressure in the aorta and the rapidity with which the urine was secreted were also recorded on the same revolving cylinder or, as continuous tracings, upon the paper of Ludwig’s kymograph. The method used for recording the changes in volume of the kidney is the same in principle as that of the plethysmograph. The kidney is enclosed in a rigid metal box, the arrangement being such that while the organ can freely expand or contract, and while the changes in volume are recorded by a lever writing with a light glass pen upon the kymograph paper, no obstruction is offered to the entrance and exit of blood by the renal vessels nor to the outflow of urine by the ureter. The kidney is surrounded by warm olive oil, which, however, is not in immediate contact with its surface, but is separated from it by a delicate flexible membrane of a kind which has already been referred to by the author in several of his published papers, and which prevents any escape of the oil by the side of the blood-vessels and other structures entering the hilus of the gland.… When the instrument is in use, the kidney lies between two delicate, exceedingly flexible membranes, which apply themselves closely to its surface and to the surface of the structures entering the hilus of the organ, and each of these membranes forms with each of the symmetrical halves of the box a chamber which is filled with oil and which communicates by a relatively wide flexible tube with the recording instrument.”
Experiment “4. After the immediate effect of the operation has passed off, the volume of the kidney will usually remain unchanged (with exception of the changes due to the pulse and respiration) for many hours unless some change in the conditions of the experiment be intentionally introduced.
“5. When the Traube-Hering curves of the blood-pressure present themselves, the volume of the kidney does not expand with the rhythmic rise in the blood-pressure. With each rise of the blood-pressure the kidney contracts, expanding with each fall of the blood-pressure. The renal vessels are, therefore, amongst those to the rhythmic contraction and expansion of which the Traube-Hering waves are due.
“6. Arrest for 3 or 4 minutes of the artificial respiration, where that is employed, and where curare has been previously injected, causes a contraction of the renal vessels (which may reach 12 per cent of the post-mortem volume of the kidney) simultaneously with the rise of aortic blood pressure which is produced by the asphyxia.
“7. Stimulation of the medulla oblongata by weak induced currents causes a powerful contraction of the renal vessels.
“8. Stimulation of the central end of a sensory nerve, e.g., sciatic, brachial plexus, splanchnic, &c., causes a contraction of the renal vessels simultaneous with the rise in the aortic blood-pressure. Stimulation of the central end of the vagus causes a contraction of the kidney (where the vagus of the other side has been cut to eliminate reflex inhibition of the heart), and the renal vessels contract whether the stimulation of the central end of the vagus cause a rise or a fall of the aortic blood-pressure.
“9. Stimulation of nearly all the roots of the splanchnic in the thorax, and of both larger and smaller splanchnic nerve-trunks causes contraction of the kidney of the opposite side. The extent to which the kidney contracts on stimulation of the splanchnic is usually very considerable. In one case the kidney contracted on stimulating with a strong induced current for three minutes to an extent which was equal to 63 per cent. of the post-mortem volume of the organ.
“10. In nearly every case stimulation of the peripheral end of the cut splanchnic at the point where it passes through the diaphragm causes contraction of both kidneys; the kidney of the side opposite to the nerve stimulated commencing to contract later than the one on the same side as the stimulated nerve.
“11. Stimulation of the central end of a sensory nerve, or of the medulla oblongata, or of the cervical spinal cord, causes a contraction of the renal vessels after both splanchnics have been cut at their point of entrance into the abdominal cavity. Vaso-constrictor influences may therefore pass from the spinal cord to the kidney by some other path than the two splanchnics.