I 



DISEASES OF THE HEART AND BLOOD, ETC. 361 



If any one asks, But what causes the heat? we answer, 

 friction of the circulation in the injured part. The flesh has 

 been crushed and mangled, and, when Nature endeavors to 

 force the current of circulation through these disjointed, 

 broken channels, there is an extra amount of friction, and 

 extra heat is the result. Even the flow of water through a 

 pipe abounding with angles is attended by an appreciable 

 rise m its temperature. In the animal system not only are 

 analogous causes now in operation, but there is increased mus- 

 cular contraction to overcome these impediments to circula- 

 tion, and muscular exertion is always accompanied by the 

 evolution of heat. 



If the circulation could be either suspended or carried for- 

 ward regularly, there would be pain, but no extra heat., t 

 "When a little abnormal heat is generated, its influence upon ♦* 

 the neighboring secretions and circulation is lite the burning ^ 

 of the wick in the lamp. In accordance with the same phys- 

 ical law by which the oil rushes to the consuming flame do 

 the blood and watery secretions move toward the injured, 

 heated part; and, as the tendency of the flame is to ignite 

 all the combustible material surrounding it, and would do so 

 unless prevented, so the heat of the injured part spreads and 

 increases until th6 whole system is involved and on fire with 

 fever heat. It is like the burning of dry wood — a little flame 

 and a little heat at first, but how soon is the whole pile on 

 fire! — a small beginning, a little heat in the injured parts 

 at first, but how soon it spreads through every portion of the 

 frame ! 



This we believe to be the true theory of fever. The blood 

 is not the generator of heat, but simply the conductor of it 

 from the burning fountain at the injured spot to all other re- 

 gions through which the blood ramifies. 



jN"ow, what are the plain, logical inferences from all this? 

 Two principal ones are all, perhaps, that practically concern 

 the farmer. The first is, to prevent the fire from burning at all, 

 if this be possible; to allow it no start whatever; to protect 

 the house from sparks and fire-brands. Let there be no oc- 



