BACILLUS PNEUMONLE. 255 



In numerous typhoid epidemics a local and seasonal 

 pre-disposition can be recognised, and Pettenkofer has, as 

 is well-known, observed that the moisture of the soil plays 

 an important part in this pre-disposition. How far this 

 view can be brought into harmony with the biological 

 characters of the typhoid bacilli will be discussed more in 

 detail in the chapter on the causation of disease. 



Bacillus pneumonia (Friedlander). 



The infectious, and at times epidemic character of 

 certain forms of pneumonia has been repeatedly pointed 

 out by various observers, for example by Kiihn, 

 Jurgensen, and others, this character leading to the 

 belief that micro-organisms may be the exciting agents 

 of the disease. In 1883, Friedlander and Frobenius, as 

 a matter of fact, found and isolated by cultivation bacteria 

 in a large number of cases of pneumonia, the organisms 

 presenting infective properties. 



The bacteria were at first only found on post-mortem Occurrence of 

 examination, especially in the alveolar exudation, mlSH^S" 01 "* 

 cover glass preparations of the juice, and in sections; 

 they were also present in the pleuritic and pericardial 

 exudation. The same bacteria have also been found by 

 Ribberfc, Ziehl, and others in the rust-coloured sputum, 

 and by Friedliindcr, in one of six cases examined, in the 

 blood obtained by cupping. 



These micro-organisms present, under the microscope, Morphological 

 the form of oval cells ; it is difficult to say whether these characters - 

 are to be regarded as oval micrococci, or as very short 

 rods with rounded ends. Friedlander has described 

 them as micrococci, but in every preparation a relatively 

 large proportion of the individuals shows such a pre- 

 ponderance of the longitudinal diameter that they 

 cannot be reckoned among the cocci ; further, iso- 

 diametric cells never occur, or only in so far as they are 

 seen in preparations, where the cells stand at right angles 

 to their long diameter ; and as also under high powers 

 of the microscope, even the shorter forms show dis- 

 tinctly parallel and longitudinal limiting lines, it seems 

 more correct to designate the organisms as bacilli. 



