There are only two points which call for especial notice with reference to diagnosis; first, the instinctive dread of liquid is to be distinguished from a delusion ; it is really occasioned by a spasmodic difficulty in swallowing, and only presents any character of mental hallucination when delirium has su pervened. Secondly, the convulsive movements must not lead us away from hydrophobia to epilepsy and tetanus ; they really have no close analogy to it, 114 the case presents neither the unconsciousness of the one, nor the perma nent spasm of the other. Strychnia poisoning resembles hydrophobia in the excitability or erethism of the nerves connected with the voluntary muscles, but in nothing else ; it cannot really simulate the disease.
c. Glanders, or Acute disease well known to veterinary sur geons in its chronic as well as in its acute form, would seem, in rare cases to be transferred to man; in the human subject it is almost always acute, and rapidly fatal. In its general features it resembles so much the effects follow ing upon the condition of pymmia, that it might admit of question whether the symptoms are not really rather due to this circumstance than to any specific character of the poison itself, were it not that in one or two essential points it seems to differ.
The history of the case records the very speedy supervention of the dis ease without any previous ailment, and sometimes without any adequate cause being assigned ; and the social condition of the patient, indicating his being employed among horses, may serve to suggest a solution of a set of anoma lous symptoms; which, as they are so rarely seen, can seldom be recognized by practitioners from experience. Most of our students must have finished their hospital attendance without having seen a case of glanders.
The symptoms are those of fever of a low type, accompanied by inflamma tion of the glands, which rapidly suppurate, forming red and painful swellings over various parts of the body ; these terminate in pustules of some size, sur rounded by a red line, which is again bounded by a white wheal; they stand in connection with inflamed lymphatics, which may sometimes be traced along their course. The disease almost invariably ends with ulceration of the mu cous membrane, and fetid discharge from the nose, and occasionally this is one of the earliest symptoms. Sometimes its course is not so defined, and it may be first recognized by the formation of one or more abscesses of some size ; this is probably explicable on the ground that, though the lymphatic system is that primarily affected, the symptoms in such cases are rather due to an altered condition of the blood, acting through the capillaries. The in flamed glands correspond to what farriers are in the habit of calling " farcy buds ;" the abscesses are more properly what in medical language have been denominated "secondary depOts ;" they form in similar situations, and, as has been already noticed in speaking of acute rheumatism, the joints are especially liable to become the seat of local swelling and inflammation.
§ 3. Colica having acquired for itself a par ticular name by its distinctive characters, and presenting a very well defined group of symptoms, the disease of which we have now to speak is in truth nothing else than a form of slow poison ing. The history of its discovery affords a very happy illustra tion of the value and uses of correct diagnosis, and of the man ner in which it may be made subservient to the real progress of medical science.
Painter's colic, as is now well known, is due to the absorption of lead. The disease is gradually developed, gaining intensity with every fresh addition to the poison already accumulated in the system ; its symptoms are in great measure local, and any peculiarities they may individually present must be again referred to; at present we have only to consider them as parts of the whole.
The preliminary inquiry into the age and social position of the patient, or some particular in his history, may afford information that he has been exposed to the influence of the poison; in other respects we learn nothing except the occurrence of occasional constipation with colicky pains. The first severe attack is usually of colic ; there is nothing, however, specific in its character ; the tongue is generally somewhat furred, and the bowels obstinately confined; there is no acceleration of pulse ; and the skin is in clined to be cold from the prostration caused by a tearing, grind ing pain, as opposed to a stitch, a sharp or darting pain ; the abdomen may be full and tympanitic, but it is not tense or tender, and is often retracted ; pressure rather relieves, while motion does not aggravate it and, therefore, in place of lying motionless with his knees drawn up, the patient rolls and tosses about in bed. The history, if it fail to point out the source of impregnation, yet assists the diagnosis by excluding other affections of a non inflammatory character, of which pain in the abdomen is a promi nent symptom. It indicates that the disorder has come on gradu ally, and thus excludes the possibility of some undigested or unwholesome food recently taken acting as the cause of colic ; it not only refers to previous attacks of less severity, but also to the gradual increase of pain during the present illness; these cir cumstances, taken along with the diffused character of the pain, render it less liable to be confounded with that attending the passage of gall-stones; while the knowledge of previous con stipation or sluggishness of bowels excludes the possibility of diarrhoea. In patients thus affected, a blue line is generally found along the edges of the gums, which, when well marked, is very conclusive. Something similar is often seen, when there is no evidence of lead poisoning, among the lower orders, whose teeth are incrusted with tartar ; and a red line is be lieved by some to exist very constantly in cases of phthisis. These cannot lead to mistakes if the lead line has been carefully observed in marked cases; and the presence of other symptoms can alone justify us in calling the case one of Colica Pictonum.
In a more advanced form of the disease paralysis is observed, especially affecting the extensor muscles of the fingers and wrists; sometimes limited to those of one or two fingers, especially the second, third, and fourth, but more generally implicatinsz all the extensors. This affection, commonly known as may be met with occasionally without the prior appearance of colic ; this is rare, however, and is chiefly seen in cases in which the lead has been introduced exceedingly slowly. In its last stages, the general health also suffers, and there is sometimes considerable emaciation ; the poison tells upon the brain, producing epileptic seizures, &c., and a well-marked condition of general cachexia is established.