THE PULSE. 243 



A weak pulse, when the arterial stream flows slowly, is caused by the feeble 

 action of the heart. It is the reverse of fever, and expressive of debility. 



The oppressed pulse is when the arteries seem to be fully distended with 

 blood. There is obstruction somewhere, and the action of the heart can hardly 

 force the stream along, or communicate pulsation to the current. It is the 

 case in sudden inflammation of the lungs. They are overloaded and gorged 

 with blood which cannot find its way through their minute vessels. This 

 accounts for the well-known fact of a copious bleeding increasing a pulse pre- 

 viously oppressed. A portion being removed from the distended and choked 

 vessels, the remainder is able to flow on. 



There are many other varieties of the pulse, which it would be tedious here 

 to particularise; it must, however, be observed, that during the act of bleeding, 

 its state should be carefully observed. Many veterinary surgeons, and gentle- 

 men too, are apt to order a certain quantity of blood to be taken away, but 

 do not condescend to superintend the operation. This is unpardonable in the 

 surgeon and censurable in the owner of the horse. The animal is bled for some 

 particular purpose. There is some state of disease, indicated by a peculiar quality 

 f the pulse, which we are endeavouring to alter. The most experienced prac- 

 titioner cannot tell what quantity of blood must be abstracted in order to produce 

 the desired effect. The change of the pulse can alone indicate when the object 

 is accomplished ; therefore, the operator should have his finger on the artery 

 during the act of bleeding, and, comparatively regardless of the quantity, continue 

 to take blood, until, in inflammation of the lungs the oppressed pulse becomes 

 fuller and more distinct, or the strong pulse of considerable fever is evidently 

 softer, or the animal exhibits symptoms of faintness. 



The arteries divide as they proceed through the frame, and branch out into 

 innumerable minute tubes, termed capillaries (hair-like tubes), and they even 

 become so small as to elude the sight. The slightest puncture cannot be 

 inflicted without wounding some of them. 



In these little tubes, the nourishment of the body, and the separation of all 

 the various secretions is performed, and in consequence of this, the blood is 

 changed. When these capillaries unite together, and begin to enlarge, it is 

 found to be no longer arterial, or of a florid red colour, but venous, or of a 

 blacker hue. Therefore the principal termination of the arteries is in veins. 

 The point where the one ends, and the other commences, cannot be ascertained. 

 It is when the red arterial blood, having discharged its function by depositing 

 the nutritious parts, is changed to venous or black blood. 



Branches from the ganglial or sympathetic nerves wind round these vessels, 

 and endue them with energy to discharge their functions. When the nerves 

 communicate too much energy and these vessels consequently act with too 

 much power, inflammation is produced. If this disturbed action is confined to 

 a small space or a single organ, it is said to be /oca/, as inflammation of the eye, 

 or of the lungs; but when this inordinate action spreads from its original seat, and 

 embraces the whole of the arterial system, fever is said to be present, and this 

 usually increases in proportion as the local disturbance is observable, and sub- 

 sides with it. 



INFLAMMATION. 



Local inflammation is characterised by redness, swelling, heat, and pain. The 

 redness proceeds from the greater quantity of blood flowing through the part, 

 occasioned by the increased action of the vessels. The swelling arises from the 

 same cause, and from the deposit of fluid in the neighbouring substance. The 

 natural heat of the body is produced by the gradual change which takes place 

 in the blood, in passing from an arterial to a venous state. If more blood is 



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