240 CHAPTER 24. 



ally gets darker. As the disease declines it becomes more copious. If 

 the patient continues to progress favorably, it resumes by degrees its 

 natural character. 



482. The Heart. 



The depression of the power of the nervous centres, which we have 

 noticed above as the main characteristic of Influenza, always affects the 

 action of the Heart. 



The heart, in order to perform its functions normally, requires to be 

 supplied with a due amount of nervous force. Its rhythms will then be 

 firm and strong, and its beats as regular as the ticks of a clock ; but if 

 the supply of nervous power is deficient and irregular, the action of the 

 heart will be feeble in tone, quick, fluttering, and often intermittent ; 

 and the impulse to the wave of blood in the arteries will be so feeble, 

 that the pulse may be extinguished by the slightest pressure of the 

 finger. These symptoms indicate the need of diffusible stimulants 

 rather than of depressants. 



Again, having regard to the theory put forward in the early pages of 

 this Chapter, that the original seat of the disease is in the microbe, and 

 that the nervous centres are only secondarily depressed through vitiation 

 of their proper nutritive stimulus, namely the blood, it is obvious that it 

 is of the greatest importance to maintain, as far as possible, the free 

 circulation of the blood — both in order that the vitiated fluid may be 

 purified by the action of the air in the lungs, and also that a better 

 supply of blood may be given to the brain and nervous centres. 



Effusion of serum, arising from congestion of the blood in the vessels 

 of the heart, is sometimes found in the pericardium. The congestion is 

 due to want of nervous power in the heart to propel forward the blood. 

 In such cases sudden death may occur when the patient in other respects 

 is doing well. 



An intermittent pulse, so long as its beats are fairly strong, is not a 

 bad symptom. It often occurs during convalescence, and may then be 

 taken as an indication of returning health, and that the heart is endea- 

 vouring to regain its power — though perhaps somewhat exhausted by the 

 attempt, and hence the occasional intermission of its beat. In the last 

 stages, when the strength is failing, an intermittent pulse is of course a 

 very bad sign. 



483, Temperature. 



During the incubation of the disease the temperature of the body 

 becomes elevated, increasing with the febrile symptoms, but decreasing 

 with the subsidence of the affection. The condition of the temperature 

 is an important item, and should be tested by the clinical thermometer as 

 explained in paragraph 217a, 



By placing the finger in the mouth increase of heat may be detected. 

 Any sudden marked decrease of temperature is a bad sign. Towards an 

 unfavorable termination of a case, the mouth and also the exhaled breath 

 will feel colder than usual. 



