234 THE ACUTE PNEUMONIAS 



Under certain circumstances other organisms, notably the b. pestis, 

 have been found to originate pneumonic processes. 



The general result of the earlier observations was to establish 

 the occurrence in connection with pneumonia of two species of 

 organisms, each having its distinctive characters, viz. : 



1. FraenkeVs pneumococcus, which is recognised to be identical 

 with the coccus of " sputum septicaemia," with Weichselbaum's 

 diplococcus pneumonias, and with his streptococcus pneumonia?. 



2. Friedldnder 1 s pneumococcus (now known as Friedlander's 

 pneumobacillus), which is almost certainly the bacillus pneu- 

 monias of Weichselbaum. 



We shall use the terms " Fraenkel's pneumococcus " and 

 "Friedlander's pneumobacillus," as these are now usually 

 applied to the two organisms. 



Microscopic Characters of the Bacteria of Pneumonia. 

 Methods. The organisms present in acute pneumonia can best 

 be examined in film preparations made from pneumonic lung 

 (preferably from a part in a stage of acute congestion or early 

 hepatisation), or from the gelatinous parts of pneumonic sputum 

 (here again preferably when such sputum is either rusty or 

 occurs early in the disease), or in sections of pneumonic lung. 

 Such preparations may be stained by any of the ordinary weak 

 stains, such as a watery solution of methylene-blue, but Gram's 

 method is to be preferred, with Bismarck-brown or Ziehl-Neelsen 

 carbol-fuchsin (one part to ten of water) as a contrast stain ; 

 with the latter it is best either to stain for only a few seconds, 

 or to overstain and then decolorise with alcohol till the ground 

 of the preparation is just tinted. The capsules can also be 

 stained by the methods already described (p. 110). In such 

 preparations as the above, and even in specimens taken from 

 the lungs immediately after death (as may be quite well done 

 by means of a hypodermic syringe), putrefactive and other 

 bacteria may be present, but those to be looked for are capsulated 

 organisms, which may be of either or both of the varieties 

 mentioned. 



(1) FraenkeVs Pneumococcus. This organism occurs in the 

 form of a small oval coccus, about 1 /x in longest diameter, 

 arranged generally in pairs (diplococci), but also in chains of 

 four to ten (Fig. 62). The free ends are often pointed like a 

 lancet, hence the term diplococcus lanceolatus has also been 

 applied to it. These cocci, in their typical form, have round 

 them a capsule, which, in films stained by ordinary methods, 

 usually appears as an unstained halo, but is sometimes stained 

 more deeply than the ground of the preparation. This difference 



