24:0 DISEASES OF THE PARENCHYMA OF THE LUNG. 



tion, or of tubercle in the lung. In Germany, the vital capacity of 

 adult healthy men is about 3,300 cubic centimetres, but it varies 

 according to sex, age, weight, and size, so that, when the stature is 

 between five and six feet, every additional inch increases the vital 

 capacity by about 130 cubic centimetres. But even after making due 

 allowance for all these conditions, there still remains considerable 

 variation, depending upon whether the patient be skilful and prac- 

 tised, or awkward and inexperienced. Hence, although a normal 

 or remarkably great capacity of the lungs indicates that they are 

 healthy, no conclusions can be drawn from a slight reduction of their 

 capacity below the normal standard, and it is only when the decrease 

 amounts to several hundred centimetres, and when it cannot be 

 ascribed to want of skill, or to lack of power, and after excluding all 

 other sources of impediment to respiration, that spirometry can con- 

 tribute toward the diagnosis of an incipient phthisis. 



We shall now endeavor to describe the main features which char- 

 acterize the separate varieties of pulmonary consumption, beginning 

 with that form in which the symptoms and termination are solely due 

 to inflammatory action. 



At the outset it not unfrequently assumes the aspect of an acute 

 disorder, with symptoms of greater or less violence. This is the case 

 when a croupous pneumonia, instead of ending by resolution, passes 

 into caseous infiltration, followed by consumption. It also occurs when 

 the blood effused into and coagulated within the bronchi and air-cells 

 during a haemoptysis causes intense and extensive pneumonia, as well 

 as in cases of invasion of the pulmonary vesicles by acute catarrh of 

 the bronchi. 



In a croupous pneumonia, when the fever persists beyond the end 

 of the first or beginning of the second week of the disease, when it 

 becomes considerably aggravated toward evening, and remits toward 

 morning, with profuse perspiration ; when the dulness in the thorax 

 continues, and when moist rdles still remain audible over the affected 

 region, and when the expectoration is profuse and muco-purulent, it is 

 to be feared that the malady has terminated in caseous infiltration and 

 consumption, which is a somewhat rare occurrence. The discovery of 

 elastic fibres in the sputa, and of cavernous sounds, dispels all doubt 

 that the tissues are hi a state of cheesy infiltration and decay. The 

 majority of patients die in a few weeks, consumed by the intensity oi 

 the fever. Far more rarely, the malady subsides after exciting the 

 very worst apprehensions ; the sputa become scanty, and the patient 

 slowly begins to improve. The dulness, however, remains. The 

 thorax sinks in over the affected region, and, after a while, well-marked 

 evidence arises of induration and contraction of the diseased portion 



