LUNGS INFLAMMATION OF THE LUNGS. 397 



INFLAMMATION OF THE LUNiiS. 



Inflammation of the lun^s is known technically as pneumonia. In this disease 



the substance of the lung itself is in a state of inflammation ; in bronchitis it is the 



air passages that are inflamed; whilst in pleurisy the inflammation attacks the 



pleura or membrane covering the lung. In acute pneumonia the fever runs as high. 



and the whole course of the disease is as abrupt as in many of the eruptive fevers. 



rule pneumonia attacks only one lung, the lower part or base being primarily 



involved. ually there is inflammation of both lungs, and then we speak of 



it as licinir a rase of double pneumonia. When pleurisy and pneumonia co-exist, as 



11 do, the complaint is known as pleuro-pneumonia. 



A consideration of the causes of pneumonia may help to throw some light upon 

 its nature and the place it should occupy in the classification of diseases. It is more 

 frequently met with in climates presenting marked and rapid variations of tempera- 

 ture than in those characterised by extremes of heat or cold. Thus in tropical 

 regions it is uncommon during the continued hot seasons, and on the other hand 

 in some of the expeditions to the North Pole, the complaint has been almost 

 unknown. It is said also to be very rare in Iceland. In Egypt, too, it is rare, 

 though bronchitis is common in the valley of the Nile. There is a general opinion 

 that pneumonia is of more frequent occurrence among the labouring than in the 

 wealthier classes of society, and that among the former those whose occupations 

 involve the severest exertion and the greatest amount of exposure are most 

 likely to sufier. In the army the soldiers are more frequently attacked than the 

 oincers. The greatest number of cases occur, as might be supposed, during those 

 months of the year in which there are the greatest vicissitudes of temperature, 

 notably in the months of April and May. Pneumonia attacks both the young and 

 the old, and it is unquestionably a common disease of early life. Men sufier very 

 much more frequently than women, and this is easily accounted for by their increased 

 exposure to climatic and other injurious influences. Opinion differs as to whether 

 pneumonia is more likely to attack the vigorous or those previously in bad health. 

 It must be remembered that the robust are more likely to be exposed to the weather 

 and to changeable climates and temperatures, for the weak and delicate stop at home 

 and take care of themselves. It has been noticed that some people are liable to 

 repeated attacks of inflammation of the lungs a peculiarity which may be due 

 either to some special but unknown constitutional predisposition, or to the fact that 

 previous attacks induce a proclivity to their return. The latter hypothesis is 

 probably the true one. The most frequent exciting or immediate cause of pneumonia 

 is cold, in some form or other, and in many cases the attack can be distinctly traced 

 to getting wet through, sitting in a draught when heated, or some similar influence. 

 Boys get heated playing football or by some other violent exercise, and then throw 

 themselves down on the grass to get cool, and often enough the result is an attack 

 of inflammation of the lungs. This is more likely to occur, the body being exhausted 

 by the previous exercise. Excessive exertion seems to act as an occasional cause. 

 In many instances pneumonia has been produced by things "going the wrong way " 

 and getting into the lungs in eating or drinking. Inflammation of the lungs is not 



