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the seventieth day. The celebrated veterinary institution at Alfort is generally satisfied with a quarantine of six weeks, in the case of a dog supposed to be affected by rabies. The developement of the poison, however, may be materially accelerated by any accident which produces a shock on the nervous system and no doubt the difference in the constitution of individuals is the cause of the difference in the extent of the intervals that are recorded between the date of the bite of the dog, and the commencement of the symptoms. These facts are useful, as materials to enable us to investigate the nature of the agent in rabies, with some prospect of
It cannot be denied that the poison, in order to operate, must be absorbed-absorption having taken place, the symptoms at once commence. We infer, therefore, that no absorption begins until within a short period before the fatal appearances are observed, and consequently that the venom is literally located in the wound where it has been deposited. Almost all the wonders that natural history has hitherto presented to our contemplation fall into the ranks of common-place events, compared with the miracle of absorption, which is every instant of our lives going on. Every atom of the body is in a course of constant renewal by means of the absorbents, and whatever is exposed to their action, they will endeavour to influence as far as circumstances will admit. The poison of rabies, however, they seem for a long time to evadeevery thing around it is withdrawn, and restored over and over again, but the virus remains untouched-nay, the little fibre, on which it lies, and which may be called its lair, is renewed again and again, whilst the grand enemy is left undisturbed. But then the virus is ultimately absorbed, and the causes which lead to the fatal event, we are not, we confess, able to explain. Such, at least, is Mr. Youatt's theory. We extract the following from one of his excellent papers :
• It enters not into the circulation, or it would necessarily undergo some modification in its passage through the innumerable minute vessels and glandular bodies which are scattered through the frame. It would excite some morbid action; or if it were not thus employed, or in the purposes of renovation or nutrition, it would be speedily ejected.
• It lies for an uncertain period dormant; but at length, from its constant presence as a foreign body, it may have rendered the tissue or nervous fibril more irritable and susceptible of impression ; or it may have attracted and assimilated to itself elements from the fluids that circulated around it, and thus increased in bulk; and at length, according to a law of chemistry, supplied by quantity that which it wanted in strength of affinity.
Whatever be the modus operandi, the parts in contact with the virus at length respond to the stimulus applied to them. The cicatrix generally begins to itch, and inflammation spreads around it. The diligent licking of some part where the mark of a bite can be traced, is an early and frequent symptom of rabies in the dog. The absorbents are now called into more powerful action. They begin to attack even the virus. A portion of the morbific matter is taken up and carried into the circulation, and disease and death ensue.'
This is as fair a solution of the difficulty, perhaps, as our present knowledge will enable us to arrive at, notwithstanding its want of analogy with numerous phenomena which we know to take place in the human body. There is some ingenuity in Mr. Murray's view of the modus operandi of the virus. He says that the inflammation developed in the cerebral surface,'-and we presume in the various viscera as well, -' is the consequence of a sympathetic, and secondary, rather than a direct action of this poison. This supposition Mr. Murray might have supported by reference to cases where some such process really takes place. Thus a person whose feet are exposed to damp will have his throat, or chest, or stomach, violently inflamed. The poison of cold, if we may so call it, is here applied to the feet, and its influence is only developed in the neck. Again we know that the bite of a rattle snake produces fatal consequences only in this direct manner : it causes intense local irritation in the part bitten, in which irritation the whole framesympathizes, and thus death ensues. The post mortem examination, however, shows no morbid appearances in the body, except only in the bitten part, and its neighbourhood. Even this fact alone would suggest to us that mere pathology will never be able to explain the influence of disease on animal life. How do we know that vital parts may not be fatally atfected, although they undergo no change of structure or colour, of which our sensés can take cognizance? Can pathology give us the most distant notion of a reason why particular agents, when introduced into our bodies, act upon particular portions only ?-Thus there are purgatives that have the whole intestines absolutely distributed in independent sections between them; aloes alone performing a peaceful pilgrimage of thirty or forty feet, to arrive at its own favourite rectum, Belladona uniformly rushes to the Iris of the eye, whilst antimony creeps in profound secresy to the skin. We are sure by every day's experience that these results spring from these causes, but the subtile medium by which they are mutually related, we know just as much of as the wisest of mankind. If then we might venture to offer a suggestion to one of whose physiological knowledge we have not a tithe, we should say to Mr. Youatt, that by confining himself to mere pathological research, he may be losing some of the best opportunities for adding to our acquaintance with the nature of rabies. It is evident, indeed, that, trusting too implicitly to pathological appearances, Mr. Youatt appears to think that he has even discovered the seat of the disease, and in explaining his theory, he carries us into some anatomical details. These details are too technical for general readers; but we may sum them up in a few words. The contents of the spinal canal at the base of the skull, and for a short way downwards, are called medulla oblongata, so that if we call the whole head the roof of the house, and the spine the column which supports it, then the medulla oblongata will be the capital of that column, according to Mr. Bell's ingenious illustration. This capital then gives forth the
nerves which connect the different parts of the body in performing the function of respiration; they are the ministers, both great and small, of that function. Mr. Youatt argues that the disease of rabies consists of an affection of the medulla oblongata, because, he says, all the external symptoms of the disease make their appearance in parts where these nerves ramify, and the medulla itself is always found inflamed after death. Mr. Youаtt mentions that Dr. Parry merely approached this theory; we can, however, inform him that the inflammation of the medulla oblongata has been already discussed by Despiney, who proposed as a cure, the paralization, if it could be effected, of the medulla. Without doubt the nerves employed in respiration are very singularly affected in this disease, and there is a fact well established, which proves that those nerves are at least the seat of its principal action. À dog under the influence of rabies, is not only not afraid of water, but he will drink it, and there is generally no spasm attending deglutition. Th same observation applies to other quadrupeds.
To man alone the symptom of the dread of drinking is peculiar. The general notion is, that it is the sight of liquid that causes the fear, but it is not so; those liquids only which are drinkable have been known to affect the patient, for labouring as he does under intense thirst, the organs by which he drinks are put in motion almost involuntarily, when he sees a liquid that he has been accustomed to drink. The reason of this symptom in man is to be found in the increased sensibility of the organ of voice, which sensibility necessarily belongs to the delicacy of mechanism required for the performance of its wonderful functions. The corresponding organ of brutes is infinitely less complicated ; so that the inference seems very naturally to arise, that the nerves of respiration are the natural prey of rabies, and that those animals who most abound with them, who possess them in such delicate combinations as they are found in the organ of speech in man, suffer most from the disease.
That the froth is the only inedium by which the virus can be communicated from a rabid dog or other animal to a healthy one, so as to produce the disease, seems to be pretty generally believed. We use the word froth purposely, because it has been said that this froth is not saliva, but that it is a mucous secretion from the lungs. This notion seems to have chiefly arisen from the circumstance that the salivary glands have been found after death totally unaffected. But this is no argument that they have not been violently stimulated during life, since we know that the excessive salivations from mercury leave no pathological change. But Mr. Youatt asserts the contrary in the case of quadrupeds, and since these last animals were included in the statement that the salivary glands were never affected, it is possible that the mistake which appears to have been made with reference to quadrupeds, may turn out also to be a mistake with respect to man. Many cases however are on record which would support the opinion that the virus may be communicated by other media than the saliva, but it has been distinctly proved that it will not pass by the mother's milk to the infant, or by the breath, or the touch, or by placing even the virulent saliva upon the healthy skin. With respect to Mr. Youatt's notion that a mucous membrane will absorb the virus, we should have less hesitation in yielding to his opinion, if we did not know that persons have sucked the virus out of a wound into their mouths, where there was plenty of mucous surface for it to act on, with perfect impunity. For the following further observations we are indebted to another paper of Mr. Youatt's.
• The virus does not appear to have the same effect on all animals. Two dogs out of three, bitten by one that is rabid, become rabid. The majority of horses inoculated with the virus perish. Cattle have more chance. The skin is looser, and less easily penetrated. A full half of those who were seized by a mad dog would escape. With sheep the bite is even less dangerous. The tooth has perhaps been cleaned in its passage through the wool. Not more than one in three who had been attacked by a rabid dog would be affected.
* The human being is least of all in danger. Mr. John Hunter supposed that, if twenty persons were bitten, probably not more than one would become hydrophobous. This, however, is calculating far too highly the chance of escape.
We have many accounts of the dreadful ravages of this disease in other countries. M. Trolliet tells us, in his valuable " Traité de la Rage," that in May, 1817, twenty-three persons were bitten by a rabid wolf, of whom no less than fourteen died, in defiance of all preventive
In 1827, two persons were bitten by a rabid dog in the neighbourhood of Ball's Pond: one of them was lost, although operated on by a very skilful surgeon.
before, a Newfoundland dog was sent to my residence, evidently unwell, but the nature of the malady not suspected. There was either something very deceptive in the case, or my assistant was unpardonably careless. The animal was dismissed with a little physic. On the next day rabies was sufficiently developed. One person only was bitten, but the poor fellow became hydrophobous.
• There can be no doubt, however, that the decided majority escape, even if no means, or those which are inert and insufficient, are adopted. Hence the falsely-acquired reputation of so many prophylactics.
• This immunity depends on various circumstances. The bitten part may be covered by wollen clothes; in passing through them, the tooth may be perfectly freed from the virus. Most of those who died in the case of Trolliet were bitten in the hand or face. Dr. Parry relates an interesting circumstance applicable to the present point. Dr. Ingenhousz was experimenting on the deadly power of the Ticunas poison. He had just envenomed the point of a knife, when it fell from his hand, and, piercing the shoe and stocking, wounded his foot. He threw himself back in his chair, and calmly said, 66 In five minutes I shall be a dead man." The five minutes, however, having elapsed without any symptoms of approaching dissolution, he ventured to remove the knife, and wash the wound. The poison, like the vitiated saliva, was in a fluid form, and it had been entirely wiped from the point of the knife in its passage through the shoe and stocking'
The difference in the results of the bite of a rabid animal in different persons, depends very much also on the part where the wound is made--for if the cuticle be thick, and the penetration of the tooth slight, there is every chance of escape. In man there is often to be found a constitution that will resist the disease, as there will be found one that is peculiarly susceptible of it. Thus it has been known that out of twenty persons bitten by the same dog, one only had the disease. We have another instance in which twelve dogs and four men were bitten by the same mad dog. All the dogs died mad, all the men escaped.
Whatever investigations and reasonings we pursue on this important subject we deem to be atterly useless, that have not for their main object a means of preventing or curing the disease. We think we may confidently say that up to this moment, we are possessed of no possible means of curing it when once it has manifested itself in the human body: but since the disease may be prevented, all our energies ought most certainly to be directed to the settle ment of the best mode of doing so. To detail the history of the thousand processes which have been tried for overcoming the malignant power of rabies, would be only reciting one out of the too many chapters of human folly and credulity: and it must be acknowledged, that the delusive promises to which so many have fallen victims in this disease, have been originated and supported in the greater number of instances by medical men themselves. The vanity of acquiring fame by a new discovery, and a mercenary desire to impose on the vulgar, have turned professional men into as mischievous enemies to the progress of true science, as ever were found in the persons of the most ignorant and presumptuous quacks, No internal remedy has ever yet proved a specific in this disease; and although Mr. Youаtt has tried a variety of drugs with apparent advantage on dogs, yet he is wise and honest enough to declare that there is not one of them to be depended on. What his skill and judgment and industry may hereafter do in discovering a specific amongst the countless tribes of healing agents that repose unknown in the wilderness of the vegetable world, we do not pretend to anticipate, though we should expect a great deal, provided a great deal can be accomplished.
Despairing, for the present, of any remedy for the disease when it has once begun, we are the more interested in considering the means by which it can be prevented. Nothing gives us a more painful impression of the ingratitude of men of the present day, than the complete forgetfulness in which they seem to be wrapt, respecting the perilous state of the canine race itself. We allude to that various class of practical philosophers-Lord Mayors, and correspondents of newspapers; Sunday editors and clerks of the police offices, who, in their excessive zeal to preserve the human race from hydrophobia, never dream of any expedient for extending similar protection to the poor dogs. If the profound view, which