The heart contracts or palpitates more quickly by twelve beats in the erect than in the horizontal attitude, but this varies in different constitutions, particularly in the native of a cold climate, who has resided long in a tropical one. In feeble people it is greater, and in all after eating, drinking, or ex ercise.
Cupping is performed with a scarificator. See Plate DXV. Fig. 1. glass cups and spirit lamp or syringe. Some art is requisite in the performance of this little operation, for the scarificator must be promptly raised during the transition of the lancets from the one side to the other, to allow them to move freely round ; and they should never be set to strike too deep, as they then completely divide the skin, and reach the cellular tissue, the blood-ves sels of which are not so large and numerous, and when wounded pour their contents into the cells. In some cases it is requisite to strike twice with the scarificator, crossing the wounds that were for merly made ; and in other instances, the cups are applied before the scarificator, in order to deter mine the blood to the part. Cupping is a most val uable remedy in many diseases, being preferable to leeches in affections of the spine and joints, without being a painful remedy.
Of the two modes of abstracting blood, viz. gen erally and locally, the latter is on all occasions pre ferable to the former, as we abstract blood more directly from the diseased part, and in all com plaints, even in fever, one organ is more affected than another, consequently general and local blood letting ought to be combined almost on all occa sions.
In the treatment of disease much reliance is placed on the nature and colour of the blood ab stracted, and many experiments have been perform ed to elucidate this interesting point. The spon taneous change of the blood, in passing from the liquid to the solid state, or its coagulation, has also been frequently the object of experiment and inves tigation. The coagulum appears to form merely from the blood being allowed to remain at rest ; and happens in the living body whenever it flows out of its natural channel, or whenever that chan nel is so enlarged as not to be able to circulate it with its accustomed rapidity and keep it fluid, as illustrated in aneurism, in varicose veins of the leg, and when an artery is secured either for aneurism or amputation. The nature and appearance of the
coagulum or clot vary very much according to the state of the constitution, when the blood is abstract ed; sometimes it is of a natural purple colour, at other times of a yellow or buff tinge, while at other times again, it is of a milky hue. The buff-colour ed blood, named also sizy and inflammatory crust, is occasionally turned up at its edges, and is then termed cupped huffy blood, and not unfrequently presents an oleaginous appearance ; this buff colour is in consequence of the red particles falling to the bottom of the coagulum, and leaving the fibrin pure on its surface. To convince us that these peculi arities of the coagulum of the blood, even the bully coat, ought never to direct us in sour diagnosis of disease, or influence us in the slightest degree in our practice, we have only to refer to the experi ments performed by Mr. Vines, detailed in the 195, 272, and 284 Numbers of the Lancet. From these it is evident, that the conclusions hitherto drawn respecting the blood of man in disease, are incorrect. . Many causes producing sudden death prevent the coagulation of the blood. During pregnancy the blood continues bully from concep tion until parturition. In pneumonia, the blood, in proportion to the quantity abstracted, becomes more bully; in many cases where only two cupfuls are taken, the last is occasionally more bully than the first ; and in some instances, when four or five are abstracted, each cupful presents a different ap pearance ; the first has a natural purple colour, the second a buff, the third cupped and bully, while the fourth and fifth are again purple. The huffy ap pearance has been attributed to the magnitude of the orifice of the vein, but this is incorrect ; the cupped appearance is certainly a better test of the existence of inflammation than the buff colour, but no weight should be given to either ; the milky colour is generally present in diabetic, bilious, and dyspeptic habits. For the chemical composition of the blood, See CHEMISTRY.