Diagnosis in man. The only additional point, to those already stated for animals, is in regard to lyssophobia. This false form of hydrophobia is usually fortified by the fact of a bite, but as a rule it lacks the exaltation of common sensation and of the special senses which characterizes genuine hydrophobia. Very often also there is a flaw in the history, the dog that inflicted the bite is unknown and may still be alive, in which case no medicine is so good as to bring the healthy dog into the presence of the patient. The dog may have been killed by an excited community without any identification of his symptoms as those of rabies or any post mortem examination to throw light on his case. The attack may have come on after a conversation on the subject of the bite, or of rabies, and perhaps, as in the case of the Montpellier cadet, long after and when the patient had for the first time heard that the dog that bit him had been mad. It may be that rabies does not exist in the district and that no other victim in man nor beast can be adduced. It may be that the patient has a nervous organization or is subject to hysteria, and therefore specially predisposed to any disease of the imagination. Such cases cannot be accepted as rabies until a successful inoculation has been made on one or more animals.
RABIES AND HYDROPHOBIA. LESIONS. TREATMENT AND PREVENTION.
Lesions: blood fluid or clot diffluent. Fauces, pharynx and larynx congested, exceptionally ulcerated. In dog, mouth cyanotic, with tenacious mucus, sublingual petechiæ and erosions, stomach contains many foreign bodies, but no food, small intestines and cæcum empty, and like stomach congested: petechiæ on skin and elsewhere, cutaneous and cardiac veins gorged, hyperæmic liver, kidneys and bladder: brain congested, capillaries dilated or blocked, hæmorrhagic, leucocytic collections in lymph spaces, nerve cells swell up with hyaline bodies near nuclei, and neuroglia has hyperplasia, especially near the respiratory centre. Congestion of nerves. Leucocytosis. Therapeutic treatment: Orrotherapy: of little avail. Nerve sedatives; darkness, quiet, nutritive enemata, chloroform, chloral, etc. Prevention: eradicate the virus; muzzle all dogs absolutely, under heavy penalty, for one year; Gower’s view; examples of muzzling; collar with name and owner, shoot all unmuzzled dogs, cage for 6 months bitten dogs and cats, also all imported dogs, shut up in cage for 10 days all dogs that have bitten; treatment of bites, tourniquet, cup, suck through tube, wring wound, cauterize—hot skewer, cautery, mineral solid caustic, mineral acids on pledget or through a tube; Pasteur method: emulsion of spinal cord (of rabid rabbit) after aseptic æration in vitro for 3 to 14 days, injected in graduated doses for 21 days, table of doses, table of mortality; Orrotherapy: by blood serum of immune animal: advantages, disadvantages—technique: Use of sterilized brain matter from rabid animal: experiments; protection by snake venom.
Pathological Anatomy. The blood is fluid or the clot diffluent. Congestion of the fauces, pharynx and larynx is patent during life but may have disappeared after death. Yet I have seen extensive ulceration of the vocal cords in a rabid cow. The congestion may extend to the trachea bronchia and lungs. In dogs the buccal mucosa is often cyanotic, covered with a thick mucus, and may present sublingual ecchymoses and erosions, and wounds of various kinds made by objects bitten or swallowed. The stomach in the same animal is usually almost pathognomonic, being filled with foreign bodies of all kinds—straw, hay, hair, wood, coal, pebbles, pieces of metal, cord, leather, cloth, earth, sand, etc.—the result of the depraved appetite. There is an absence of normal food principles in stomach and small intestines and the cæcum and colon are usually empty. The gastric mucosa is congested, and may be wounded and its contents mixed with blood. Such a condition of the stomach in a dog, that has been bitten, and which after a customary incubation period has shown symptoms like those of rabies, is virtually diagnostic.
The following lesions are common to man and animals: Marked emaciation, cyanosis or petechiæ in skins that are naturally white, early sepsis, cutaneous veins and heart gorged with dark inspissated blood, hyperæmic liver and kidneys, and slightly congested, petechiated empty bladder.
The most important lesions, however are those of the central nervous system. In seven cases out of nine, Gowers found these very distinct. There were vascular disturbance, capillary dilatation, capillary clots, minute hæmorrhages, and accumulations around the affected capillaries of leucocytes occupying the lymph spaces. Benedikt and Babes attach much importance to the formation of hyaline patches in the thickened walls of the vessels and around them, compressing the vessels in some cases to virtual obliteration. The nerve cells swell up, and show small hyaline bodies in the vicinity of the nuclei, and these latter finally disappear. Germano and Capobianco found in addition marked hyperplasia of the neuroglia. Babes, who looks on these changes as pathognomonic, takes a small portion of spinal cord, hardens it in alcohol for 24 hours, stains it with aniline red and examines for the characteristic hyaline nodes.
These brain lesions have been found mainly in the medulla near the floor of the fourth ventricle and the respiratory center, but they are also to be found in other parts of the encephalon and spinal cord. The greater constancy of the medullary lesions serves to explain the characteristic symptoms.
Congestions of the peripheral nerves have also been found. Lüttkemüller found in rabies a moderate increase of the white blood corpuscles and a great number of microcytes.
Therapeutic Treatment. It was long thought that rabies was necessarily fatal, as indeed nearly all developed cases are to the present day. For this reason and much more on account of the risk of preservation and propagation of the deadly germ, the attempts at curative treatment in the lower animals have been looked on as utterly unwarranted or absolutely criminal. Yet it is now known that very exceptionally a recovery takes place, and in that case immunity for the future may be counted on. Yet the frightful danger attendant on the preservation and treatment of a rabid animal, may well forbid the keeping of any of the lower animals affected by rabies unless it be in the safest seclusion and for the production of immunizing or curative products.
Orrotherapy with the blood serum of an immunized animal is of little value, and attended by risk from the rabid animal, but will be noticed below as a prophylactic.