204 ANTHROPOLOGY. 



cular region. It thus comes into play in such diseases as plethora, inflam- 

 mation, congestion, cramps, fever, &c. The principal methods of extracting 

 blood are as follows. 



1. Scarification. This consists in making numerous superficial inci- 

 sions in the skin of a particular spot with a lancet {pi. 140, figs. 1 and 2), or 

 with some special apparatus, for the purpose of removing fluids from the 

 capillaries or from the cellular tissue. 



A convenient instrument for this purpose is known as the scarificator 

 {fig. 31 a b), which consists of a cubical brass box in which ten to sixteen 

 lancets turn on a common pivot so as to have their points project above the 

 surface ; the extent of their projection is regulated by a screw. On draw- 

 ing back the handle, the lancets disappear beneath the surface and are there 

 held by a spring. Bringing the scarificator over a given spot, and loosening 

 the spring, the lancets will all fly out at once, and produce as many delicate 

 incisions. The operation of rjipping is usually connected with the use of 

 this instrument, and is intended to focilitate the flow of the fluids to be 

 extracted. The cups, consisting of little bells of glass, are laid over the spot 

 scarified, and the included air exhausted by means of a burning piece of 

 paper, previously introduced. The pressure of the external air causes the 

 blood to flow freely. Sometimes the exhaustion is produced by means of a 

 small air-pump. 



2. Venesection, or Blood-Letting, is a time-honored operation, con- 

 stantly brought into requisition ; it consists in opening a single vein, and 

 permitting as much blood to flow therefrom as may be desirable. 



The surgical apparatus necessary in blood-letting includes a soft linen 

 bandage of about a yard in length and two inches in breadth ; a bleeding 

 lancet {fig. 1), which, in the hands of a skilful operator, has great advan- 

 tages over the spring lancet ; a compress formed of a roll of linen about a 

 yard long and two inches broad ; proper vessels for receiving the blood ; a 

 soft sponge, and clean lukewarm water. 



Bleeding with the spring lancet {fig. 32 a h^ the common spring lancet ; 

 fi{). 33, the lancet of Walbaum ; fig. 34, the lancet of Perret, a, i, c, various 

 blades) requires the same preparations as with the common lancet. After 

 the vein has been prepared, the spring of the lancet is to be set, and the 

 blade brought over the spot where the incision is to be made. On touching 

 the spring, the blade is liberated and pierces the vein. 



PI. 139, fig. 1, bend of the elbow or the usual spot for blood-letting, the 

 skin supposed to be removed : ', trunk of the basilic vein in the depression 

 along the inner border of the biceps brachii; '', cephalic vein on the outer 

 side of the biceps, and separated from the nerve by the fascia ; '' ', basilic 

 and cephalic veins on the forearm ; *, a probe introduced under the brachial 

 artery ; ^, median vein which communicates with the deep vein in front of 

 the opening in the aponeurotic membrane, and divides above to unite by a 

 short branch (median cephalic) with the cephalic vein, and by a longer 

 branch (median basilic) with the basilic vein ; ", superficial posterior basilic 

 vein ; ^, superficial posterior cephalic vein ; ", trunk of the great internal 

 brachial nerve on the inside of the basilic vein ; ", muscular cutaneous 

 210 



