STORAGE OF HEAT. FEVER. 335 



produced and the amount given off, it is clear that heat must be stored up in the 

 body when the evolution of heat is diminished. The skin is the chief organ 

 regulating the evolution of heat ; when it and its blood-vessels contract, the heat 

 evolved is diminished, when they dilate, it is increased. Heat may be stored up 

 when 



(a) The skin is extensively stimulated, whereby the cutaneous vessels are temporarily con- 

 tracted, (b) Any other circumstances prevent heat from being given off by the skin, (c) 

 When the vaso-motor centre is excited, causing all the blood-vessels of the body those of the 

 skin included to contract. This seems to be the cause of the rise of temperature after trans- 

 fusion of blood, and the rise of temperature after the sudden removal of water from the body seems 

 to admit of a similar explanation, as the inspissated blood occupies less space, and the con- 

 tracted vessels of the skin admit less blood, (d) When the circulation in the cutaneous vessels 

 of a large area is mechanically slowed, or when the smaller vessels are plugged by the injection 

 of some sticky substance, or by the transfusion of foreign blood, the temperature rises ( 102). 



It is also obvious that when a normal amount of heat is given off, an increased 

 production of heat must raise the temperature. The rise of the temperature after 

 muscular or mental exertion, and during digestion, seems to be caused in this way. 

 The rise which occurs several hours after a cold bath is probably due to the reflex 

 excitement of the skin causing an increased production (Jiirgensen). 



When the temperature of the body, as a whole, is raised 6 C, death takes place, 

 as in sunstroke. It seems as if there was a molecular decomposition of the tissues 

 at this temperature; while, if a slightly lower temperature be kept up continuously, 

 fatty degeneration of many tissues occurs (Litten). If animals, which have been 

 exposed artificially to a temperature of over 42 to 44 C, be transferred to a 

 cooler atmosphere, their temperature becomes sub-normal (36 C), and may remain 

 so for several days. 



220. FEVER. Fever consists in a " disorder of the body heat" and at the same time there 

 is greatly increased tissue metabolism (especially in the muscles). Of course the mechanism 

 regulating the balance of formation and expenditure of heat is disturbed. During fever the 

 body is greatly incapacitated for performing mechanical work. It is evident, therefore, that 

 the large amount of potential energy transformed is almost all converted into heat, so that the 

 non-transformation of the energy into mechanical work is another important factor. We may 

 take intermittent fever or ague as a type of fever, in which violent attacks of fever of several 

 hours' duration alternate with periods free from fever. This enables us to analyse the symptoms. 

 The symptoms of fever are : 



(1) The increased temperature of the body (38 to 39 C, slight; from 39 to 41 C. and up- 

 wards, severe). The high temperature occurs not only in cases where the skin is red, and has 

 a hot burning feeling (calor mordax), but even during the rigor or the shivering stage, the 

 temperature is raised. The congested red skin is a good conductor of heat, while the pale 

 hloodless skin conducts badly; hence, the former feels hot to the touch ( 212). 



[The following table in C. and F. indicates generally the degree of fever : 



! 



Moderate fever. 



J- High fever. 

 Hyperpyretic. 



] 



(2) The increased production of heat is proved by calorimetric observations. This is, in 

 small part, due to the increased activity of the circulation being changed into heat ( 206, 2, a), 

 but for the most part it is due to increased combustion within the body. 



(3) The increased metabolism gives rise to the "consuming" or "wasting" character of 

 fever, which was known to Hippocrates and Galen. In 1852 v. Barensprung asserted that 

 "all the so-called febrile symptoms show that the metabolism is increased." The increase of 

 the metabolism is shown in the increased excretion of CO 2 = 70 to 80 per cent., while more O is 

 consumed, although the respiratory quotient remains the same. According to D. Finkler, the 

 C0 2 excreted shows greater variations than the O consumed. The excretion of urea is increased 

 i to . In dogs suffering from septic fever, Naunyn observed that the urea began to increase 

 before the temperature rose, " prefebrile rise." Part of the urea, however, is sometimes retained 

 during the fever, and appears after the fever is over, " epicritical excretion of urea." The uric 



