Black Quarter, also called Black Spald, Black Leg, Quarter Evil, Blood Striking, Symptomatic Charbon, Chabert's Disease, is a contagious and infectious disease of cattle due to the presence of a specific organism, which usually exerts its malignant influence upon the tissues immediately beneath the skin. It is caused by rich pasture on stiff, retentive, and undrained soil; or by sudden changes from poor to rich keep, particularly with animals in good health, thriving well, and putting on beef. It is a disease which affects animals of all ages, from six months to six years old, though by far the largest number of victims is in those ranging from nine months to two years old. The malady occurs chiefly in spring and autumn, though seen at all periods of the year.
The premonitory signs are often overlooked. The animal may be observed with a sleek coat, voracious appetite, quick staring look, suddenly to stop feeding; the eyes become bloodshot; there is slight salivation or foaming at the mouth; and in the very great majority of cases there is lameness in one of the limbs, the cause of this lameness being the rapid formation of a tumour at the top of the limb. This tumour is at first hot and painful to the touch, but soon becomes dead in its centre, and the skin covering it becomes crackling, and crepitates. Occasionally the tumour may form in the head, neck, dewlap, the joints, or in the body itself, but usually in the withers and loins. The animal's temperature rises to 103°, or as high as 107° F. The pulse becomes rapid and weak; the pain is excessive. Animals in this state are costive at first, but occasionally violent diarrhoea supervenes, and the excrement is tinged by black extravasated blood, tumour rapidly increases in size, the lameness becomes more intense, fits supervene, and death usually occurs in from four to forty-eight hours, though some cases prove lingering. The disease is almost invariably fatal, and no treatment is of any avail.
Post-mortem Appearance.—Owing to decomposition taking place even before death, the first thing noticed is the great swelling of the body, due to the evolution of gases, not only under the skin, but also in the stomach and bowels. The blood is found to be red, and to coagulate readily, so showing that the disease is not a form of anthrax, as had always been supposed until quite recently. The lungs are congested, all the viscera are spotted with red patches, and are more or less congested. The specific lesions are found in the region of the tumour, which is indistinctly divided into three zones. Microscopic examination of a portion of the outer or middle zones reveals the presence of large numbers of micro-organisms, known as the Bacteria of Chauveau, which often contain one or more spores, and which, if introduced under the skin of healthy cattle, will produce black quarter.
Prevention is of two kinds. First, to render the pastures unfit to propagate the poison, by deep draining, whereby many pasture-lands, after having repeatedly ruined tenant-farmers, have been rendered perfectly safe from losses by black quarter; and, secondly, to render the system of the animal innocuous to the poison by protective inoculation. The method of inoculation which has met with the greatest success, both in England in a small way, and in France in tens of thousands of cases, is as follows: Take from an animal just dead of the disease a portion of the middle zone of the tumour, cut into small pieces, mix in a mortar with three times its weight of distilled water, then triturate; remove from mortar, and roughly strain through a piece of muslin; then carefully strain through three folds of fine muslin. Of the clear fluid so obtained take from 5 to 10 minims in a small syringe specially made for the purpose (Pravaz's), and inject it into the jugular vein of the healthy animal. The animal must be carefully secured before the operation. The needle of the syringe is then pressed through the skin into the vein, and then the piston of the syringe slowly pressed upon. During this part of the operation an assistant should pour on the part some solution of boracic acid, so as to destroy any of the virus which might escape. The great difficulty of this operation is, that if the very slightest particle of the virus, instead of entering the circulation, should come in contact with any part of the wound, black quarter will be the result, and not protection. The second method is to take small pieces of the tumour and desiccate at a high temperature, and to introduce some of the dust so obtained under the skin of the healthy animal—a method which has not proved very certain or successful.