When the vein is firmly pressed with the fingers of the left hand, the blood is prevented from descending, and that part of the vein which is above the fingers is considerably distended, and becomes very conspicuous. In this state it may be easily opened with a lancet held in the right hand. The vein will continue to bleed as long as the pressure below is continued.
Farriers bleed with a fleam, which, though apparently a clumsy method of operating, is certainly safer than the lancet in unskilful hands. In topical bleeding, a vein is chosen as near as possible to the affected part, or the vessels covering the part are opened: in the inflammation of the eye, for example, it is done by scarifying the inner surface of the eyelid, or by opening a small vein which is easily seen going from the inner corner of the eye towards the nose. I do not think, however, that either of these operations do any good; indeed that of scarifying the eyelids is often, I believe, injurious.
A graduated tin vessel, capable of containing six or seven quarts, is very convenient for the purpose of receiving the blood; every pint being marked on the inside of the vessel, so that the quantity of blood that is taken off may be exactly known. The blood should always be preserved, that we may judge from its appearance of the nature of the disease, and whether it is proper or not to repeat the operation. When it continues fluid a considerable time, it denotes an inflammatory state of the system. Should a whitish or light buff-coloured jelly appear on its surface, after it has coagulated or settled, and should this jelly be of considerable thickness, rather firm, not easily penetrated by the finger, we may be satisfied that the horse’s complaint is inflammatory; that bleeding was a proper remedy; and that, if the symptoms continue, the operation may be repeated with advantage: but if the blood coagulates quickly, is uniformly of a dark liver colour, loose and easily broken, with a considerable quantity of water upon its surface, it denotes debility, and shows that the disease arises from a weakness of the system; that instead of bleeding, tonic and cordial medicines are to be employed, with every thing that may tend to restore the animal’s strength.
In order to judge correctly by the appearance of the blood, it should be drawn from a large orifice, and not suffered to run down the sides of the vessel which receives it. The first quantity that is drawn should be put aside for examination, and not shaken or disturbed in any way until it has perfectly coagulated.
When bleeding is employed as a preventive, or in any slight complaints, from two to three quarts may be taken off, according to the horse’s strength and condition; but in cases of internal inflammation, or fever, a more copious evacuation is necessary.
When horses are taken from camp or grass, and put into warm stables, they are very subject to inflammatory complaints and dangerous fevers: under those circumstances, moderate bleeding now and then will prevent such diseases. Horses that are getting into condition, as it is termed, are liable to similar disorders, unless moderate bleeding is occasionally employed. I am inclined to believe, however, that it is a bad practice to bleed often upon trifling occasions; it is liable to induce a plethora or fulness of habit, whereby a horse is rendered more susceptible of disease than he would otherwise be. Moderate purging and regular exercise, with a proper regulation of diet and temperature, are fully adequate to the prevention of disease on those occasions; but these are too often neglected.
It has been asserted that it is seldom necessary to pin up the orifice, which is made in the skin by bleeding. I grant there is not often any danger to be apprehended from its bleeding again; but unless it is pinned up, that is, unless the lips of the wound are brought into contact, and kept in that situation, by passing a pin through the edges of the skin, and twisting a little tow round it, as is generally done by farriers, inflammation and swelling will sometimes take place in the wound, and matter will form in consequence. The fleam has been found upon many occasions, particularly for opening the neck vein, a better instrument than the lancet; the latter makes an orifice in the skin, scarcely larger than the vein; and as the horse is generally a little restless, the blood soon gets between the skin and the vein, plugging up the orifice in the latter, and sometimes diffusing itself in the cellular membrane, so as to cause a swelling. The lancet, however, in skilful hands is a neater method, and more convenient for horses that are very shy and difficult to be bled in the common way.
Dogs may be conveniently bled by the jugular or neck vein, with a fleam, or with a common lancet; but the latter is much preferable. A ligature being put round the lower part of the neck, and the head being held up, the vein will swell and protrude itself on each side of the windpipe, about one inch from it. It will, however, be necessary previously to cut the hair away, if it be very thick; after which, the puncture can be easily made with a lancet, the operator leaning over the dog. Nothing is necessary, in general cases, to stop the bleeding, but to remove the ligature; nor is any pin, plaister, or bandage, requisite for the orifice. When circumstances such as the want of a regular operator, or when the amateur is called on to deplete his own dog suddenly, as in the field, when the means of venesection by the neck are not at hand; in any such case the ear may be punctured, or an incision may be made on the inner side of the flap of it, choosing, if possible, the course of a vein for the puncture, but avoid passing the instrument through the ear. Or the tail may be cut in desperate cases; but, when this is done, it is better to cut off a small piece than to merely make an incision underneath; for I have seen, when this has been injudiciously done, the whole tail in a state of mortification.
The quantity of blood drawn should be regulated by the size of the dog: for a very small dog, one or two ounces are sufficient; for a middling sized dog, three or four ounces; and for a large dog, five, six, seven, or eight ounces, according to the size and strength of the patient, and the nature of the disease he labours under.—White.—Blaine.