"PAIN INCREASES (BLOOD)-PRESSURE. In four cases of trauma (injury), a rise of 20 to 40 was noted upon pressure upon a nerve. Even in a healthy person, pinching the integument was noted increase the pressure."[2]
[2] Crile "On Blood-Pressure," p. 341.
It would seem unnecessary to acc.u.mulate evidence regarding a physiological phenomenon so long and so firmly established. We may therefore take it for granted that in a living animal or in a human being, as a general rule, the irritation of a sensory nerve will cause a rise of blood-pressure.
Let us now suppose that an animal destined to be vivisected lies before us, "stretched" on the vivisection dog-board, so securely fastened that voluntary movement is almost impossible. An incision has been made in the neck, and in the princ.i.p.al artery has been inserted a part of a delicate instrument designed to indicate the fluctuations of the blood-pressure of the animal. The sciatic nerve has been laid bare; the animal is supposed to be under the influence of an anaaesthetic continuously administered, and if our imagination is vivid and our faith implicit, we may believe that no suffering will be felt. BUT HOW MAY WE BE CERTAIN? This question came up more than once before the Royal Commission on Vivisection. How can one tell that an animal may not be insufficiently anaesthetized IF IT CAN MAKE NO SIGN, WHEN ALL THE ACTS BY WHICH IT MIGHT EVINCE ITS SUFFERING ARE CAREFULLY RESTRAINED? The animal which lies before us cannot move; every physical movement is as far as possible totally suppressed. It cannot use its voice, for the trachea is cut and otherwise used. ARE THERE NO MEANS WHEREBY WE CAN TELL WHETHER THE ANIMAL IS SUFFERING what one of the Royal Commission called "a nightmare of suffering"?
The answer to this question has been given by some of the leading physiologists of England.
Dr. J. M. Langley, professor of physiology in the University of Cambridge, a Fellow of the Royal Society, gave explicit testimony on this point. His examiner was desirous of knowing upon what he would depend, other than upon the dose of the anaesthetic and watchfulness, if in the animal he could see nothing that would satisfy him.
"There is the state of the blood-pressure, which would indicate to some extent the reflexes on the vascular system," Professor Langley replied.
"WOULD PAIN CAUSE AN INCREASE OF BLOOD-PRESSURE?"
"IT WOULD CAUSE A RISE OF BLOOD-PRESSURE," replied the physiologist.
Of course, he insisted upon the sufficiency of the anaesthesia, but he had made the most important admission which his evidence affords. IF PAIN WERE FELT, IT WOULD CAUSE A RISE OF BLOOD-PRESSURE.
Dr. W. E. Dixon of King"s College, London, representing one of the sections of the Royal Society of Medicine, gave evidence before the Royal Commission on various matters pertaining to anaesthesia. Dogs, he a.s.serted, "very easily die of chloroform; but if one goes sufficiently slowly they never die." (18,677)[1]
[1] Figures in parentheses refer to the questions or replies in the printed evidence.
"Supposing you were giving chloroform with CURARE, then it might be said you were not giving enough chloroform. BUT YOU CAN SEE WHETHER YOU ARE GIVING ENOUGH BY LOOKING AT THE BLOOD-PRESSURE." (18,690) Professor Dixon tells us that one of the gauges used for determining whether anaesthesia is present or not IS THE BLOOD-PRESSURE. "The blood-pressure goes DOWN BECAUSE THE CHLOROFORM IS GIVEN. The heart beats more feebly; therefore the blood-pressure goes down." (18,742)
Another expert physiologist, whose testimony on this point is enlightening, was Dr. Eh. H. Starling, professor of physiology at University College, London.
"Are there any means, other than the cries or struggles of the animal, by which you can tell whether the anaesthetic is pa.s.sing off?"
"YES, YOU CAN TELL IT BY THE BLOOD-PRESSURE," Dr. Starling replied. "When one is working without curare, one notices THAT THE PRESSURE GOES UP, and then, if one does not attend to it, after that comes a little movement, AND YOU GIVE MORE ANAESTHETIC." (4,054)
We need not follow Professor Starling in his repeated a.s.surances of complete anaesthesia in his vivisections; all this is merely an expression of faith in the accurate and perfect working of his instruments, a faith which some of the Commissioners did not share.
What interests us is the statement that IF THE ANAESTHESIA IS IMPERFECT, THE BLOOD-PRESSURE WILL REVEAL IT. "The pressure goes up"; there is some slight motion on the part of the animal; IT FEELS, and that returning sensibility to painful impressions is indicated by an increase in the pressure of the blood.[1]
[1] Sir Victor Horsley admitted that "changes in the blood-pressure"
afford an indication whether anaesthesia is perfect or not (Ques. 16,057).
But how is the measurement of the blood-pressure to be ascertained?
One of the instruments in use is thus described:
"The pressure exerted upon the blood in the arterial system may be measured by attaching the carotid artery of a living animal to a reservoir of mercury, provided with an upright open tube or pressure- gauge.... Under pressure of the blood, the mercury rises in this tube, and the height of the mercurial column becomes an indication of the pressure to which the blood itself is subjected within the artery.
The arterial pressure is found to be equal to the average of a column of mercury 150 millimetres, or 6 inches, in height."
Instruments for ascertaining the blood-pressure in human beings record it merely for a moment or two. In experimenting upon a living animal, an incision is made in the neck, the princ.i.p.al artery exposed and severed, and connected with the recording instrument.
"Pain" is a word which as a rule the modern physiologist prefers to exclude from his vocabulary. "We know absolutely nothing about pain except that which we ourselves have suffered," says a leading experimenter. We are unable neither to see, hear, smell, taste, or feel the pain of another being, and although the cries or struggles of an animal which is being vivisected may suggest that it is experiencing intense agony, the physiologist insists that in reality we know nothing about it, and we can only infer that it is experiencing something which our reason suggests that we should feel in its place. Of course we might say the same thing regarding agony undergone by another human being. What the physiologist does is note the phenomena following the stimulation of nerves, and to register it by appropriate instruments.
To stimulate a nerve is to excite its activity in some way. When the dentist touches with his instrument the exposed nerve of a tooth, there is immediate "stimulation," as many of us have had reason to a.s.sert, even if the dentist can know nothing of our sensations, and can only infer them by remembering his own. One may stimulate the nerve of a vivisected animal by mechanical means, by pinching or sc.r.a.ping it when exposed; and although the movements of the animal may indicate an exquisite sensibility, yet other methods are more effective for the purposes of the experimenter. "Electricity,"
Professor Austin Flint tells us, "is the best means we have of artificially exciting the nerves. Using electricity, we can regulate with exquisite nicety the degree of stimulation. WE CAN EXCITE THE NERVES LONG AFTER THEY HAVE CEASED TO RESPOND TO MECHANICAL IRRITATION." A French vivisector, M. de Sine"ty, removed the b.r.e.a.s.t.s of a female guinea-pig, nursing its young, and laid bare the mammary nerve, and he tells us that "the animal exhibits signs of acute pain, ESPECIALLY WHEN THE NERVE IS STIMULATED BY AN ELECTRIC CURRENT."[1]
[1] Gazette Me"dicale de Paris, 1879, p. 593.
In 1903 there was published in America an account of a large number of vivisections involving blood-pressure which a well-known experimenter had made, either personally or by his a.s.sistants. The number of dogs thus sacrificed was no less than 243; the experiments to which they were subjected amounted to 251. Ether alone was used in 107 experiments, or about 43 per cent. of the whole number; ether and morphia were employed in 80 experiments, or 32 per cent. of the total. Chloroform combined with ether was used but ONCE. In no less than 15 per cent. of the experiments no anaesthetic whatever is named, and CURARE was employed in nearly 10 per cent. of the investigations.
Why was curare used? We have seen that the professor of physiology in Upsaal University regards it as "the most cruel of poisons." An animal under its influence, Professor Holmgren tells us, "changes instantly into a living corpse, WHICH HEARS AND SEES AND KNOWS EVERYTHING, but is unable to move a single muscle, and under its influence no creature can give the faintest indication of its hopeless condition." The French vivisector, Claude Be"rnard, tells us frankly that death under the influence of this poison "is accompanied by sufferings the most atrocious that the imagination of man can conceive." Precisely the reason why this poison was employed in the investigations before us we have no means of knowing by anything the vivisector has stated in his report. He tells us, indeed, that "the animals were all reduced to full surgical anaesthesia before the experiments began, a nd were killed before recovery from the same." We see no reason for doubting why this may not have been true. It is quite probably that as a rule the preliminary cutting operations necessary were made while the animal was deeply insensible. But was this deep insensibility maintained for hours? Was it so absolute that doubt is impossible?
Since it is certain that the irritation produces a rise in blood- pressure, was this phenomenon never witnessed during the terrible operations to which these dogs were subjected for hours at a time? If, as Professor Langley of the University of Cambridge explained, pain "WOULD CAUSE A RISE OF BLOOD-PRESSURE," was this sign of agony ever evoked when the bare nerve was subjected to "stimulation," or the paws "slowly scorched" one after another? Let us see.
We observe that as a rule each vivisection consisted of two procedures, aside from the preliminary operation. In the first place, the normal pressure of the blood was reduced by various methods, calculated to depress the vital powers of the animal, and to induce a condition of collapse, and this was followed by such "stimulation" of nerves as would tend to cause the blood-pressure to rise in an animal not perfectly anaesthetized. The means taken to depress the vital powers were as varied as the ingenuity of the vivisectors could devise. Sometimes it was accomplished by skinning the animal alive, a par of the body at a time, and then roughly "sponging" the denuded surface. Sometimes it was secured by crushing the dog"s paws, first one and then the other. Now and then the dog"s feet were burnt, or the intestines exposed and roughly manipulated; the tail was crushed, the limbs amputated, the stomach cut out. Then came the "stimulation"
of the exposed nerve, carried on and repeated sometimes until Nature refused longer to respond, and death came to the creature"s relief.
No torments more exquisite were ever perpetrated unless absence of feeling was completely secured. Was it so secured? Let the experimenter"s own report give us the facts, remembering that if there was pain, "THE BLOOD-PRESSURE WOULD RISE."
EXPERIMENT 42. The material used was a little dog, weighing only 11 pounds. How it was "reduced to shock"--whether by skinning or crushing--we are not informed; all we know is that it was "reduced to shock." The sciatic nerve was exposed, the artery in the neck laid bare, and the instrument for measuring the blood-pressure carefully adjusted. Ether, we are told, was used. Was all sensibility thereby wholly suppressed? Let us see what is revealed by the changes of the blood-pressure.[1]
[1] In all experiments cited in this chapter the italics are not in the original descriptions.
"10.30 a.m. Sciatic nerve stimulated. SLOW RISE IN BLOOD-PRESSURE.
10.35 a.m. Sciatic nerve stimulated. RISE OF BLOOD-PRESSURE.
10.51 a.m. Sciatic nerve stimulated. RISE OF BLOOD-PRESSURE.
11.30 a.m. Sciatic nerve stimulated. RISE OF BLOOD-PRESSURE 13 MILLIMETRES.
11.59 a.m. Sciatic nerve stimulated. RISE OF BLOOD-PRESSURE 5 MILLIMETRES."
Noon has come. It is the hour when experimenters need their accustomed refreshment, and we note a long interval during which there were no observations. The victim lies stretched upon the rack. After nearly two hours the pastime began again, or, we may say, "the young scientists resumed their arduous labours."
"1.55 p.m. Sciatic nerve stimulated. ABRUPT RISE OF BLOOD-PRESSURE 17 millimetres.
3.3 p.m. Sciatic nerve stimulated. RISE OF 14 MILLIMETRES.
4.44 p.m. Sciatic nerve stimulated. RISE OF 2 MILLIMETRES."
The little animal is growing weaker. For more than six hours it has been on the rack. The play upon its nervous system is about over. At five o"clock the dog died.
The full details of this experiment do not here concern us, and are not given. Whether useful or not is another matter Pain, said Professor Langley, "WOULD CAUSE A RISE OF BLOOD-PRESSURE." Did not the blood-pressure rise when this creature"s nerve was stimulated?
EXPERIMENT 114. In this experiment four dogs were simultaneously vivisected. Some of them lasted but a short time; but one--a young dog--was "in splendid condition," and subserved the object of the vivisection for many hours. The usual incisions were made in the trachea and carotid artery, and the femoral vein and sciatic nerve was exposed. At 10.59 a.m. the blood-pressure was found to be 125 milli- metres; at 10.42 it had been reduced to 99 millimetres--by what means we are not informed. Further details are as follows:
"11.42 a.m. Blood pressure 99 millimetres.
11.45 a.m. Stimulated sciatic nerve. PRESSURE ROSE TO 115 MILLIMETRES.
12 midday. Blood-pressure 95. Sciatic nerve stimulated: BLOOD-PRESSURE 115.
12.19 p.m. Blood-pressure 92.
1.23 p.m. Blood-pressure 108; sciatic nerve stimulated.
1.26 p.m. Blood-pressure 110; three minutes later."
Between 1.29 p.m. and 2.19 p.m. there is no record of any observations. Perhaps we may venture the hypothesis that during this period of nearly an hour"s duration, the young experimenters went out to luncheon. The dog, while stretched upon the rack, could have had no other refreshment than cessation from the stimulation of its nerves.
But after about an hour"s intermission the young vivisectors would seem again to have begun their observations concerning the effect produced by stimulating the sciatic nerve. What was that effect? It appears to have been very uniform.
"2.28 p.m. Sciatic nerve stimulated. ABRUPT RISE AND FALL IN BLOOD-PRESSURE.
3.32 p.m. Sciatic nerve stimulated. RISE AND FALL IN BLOOD-PRESSURE.
4.16 p.m. Sciatic nerve stimulated. BLOOD-PRESSURE ROSE TO 120, FALLING TO 105.
4.34 p.m. Sciatic nerve stimulated. ABRUPT RISE AND FALL OF BLOOD-PRESSURE.
4.53 p.m. Sciatic nerve stimulated. THE USUAL RISE AND FALL FOLLOWED."