TYPES OF PNEUMONIA. 185 



which both an acute croupous condition and an acute 

 catarrh occur in the same lung. 



Besides these two clinical types of pneumonia there 

 is another group of cases which are somewhat loosely 

 denominated septic pneumonias, and which may arise in 

 two ways: (i) by the entrance into the trachea and 

 bronchi of discharges, blood, etc., which form a nidus for 

 the growth of septic organisms, and thus infect the tissue of 

 the lung; (2) from secondary pyogenic infection by means 

 of the blood stream from suppurative foci in other parts of 

 the body. (See Chapter on Suppuration, etc.) 



We shall see that bacteria have been found associated 

 with all these types of pneumonia. Special importance is 

 attached to acute croupous pneumonia on account of its 

 course and characters, but reference will also be made to 

 the other forms. 



Historical. Acute lobar pneumonia for long, both 

 popularly and medically, had been supposed to be an 

 effect of exposure to cold ; but there were not wanting 

 those who were dissatisfied with this view of its etiology. 

 Not only did many cases occur where no such exposure 

 could be traced, but it had been observed that the disease 

 sometimes occurred epidemically, and was occasionally 

 contracted by hospital patients lying in beds adjacent to 

 those occupied by pneumonia cases. Further, the sudden 

 onset and definite course of the disease conformed to the 

 type of an acute infective fever. It was thus suspected 

 by some that it might in reality be due to a specific 

 infection. After the commencement of bacteriological 

 investigation, various observers described the occurrence of 

 micro-organisms in the lungs or other organs of persons 

 dead of the disease. The first real contributor, however, 

 to the modern view of m its etiology was Friedlander. In 

 1882 and 1883 tms author published several papers giving 

 the result of his researches. Briefly, these results were as 

 follows. In the bronchial contents and in sections of 

 pneumonic lungs, there were organisms which he described 

 as cocci, adherent usually in pairs, and which possessed a 



