BACTERIA IN PNEUMONIA 199 



stained by the methods already described (p. 102). 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) Fraenkel's Pneumococcus. This organism occurs in the form 

 of a small oval coccus, about 1 /^ in longest diameter, arranged 

 generally in pairs (diplo- 



cocci), but also in chains /" 



of four to ten (Fig. 64). *", /; * 



The free ends are often .*, 3 



pointed like a lancet, hence " v v> * 



the term diplococcus lance- 

 olatus has also been ap- *'/ 



plied to it. These cocci ."_ , 



have round them a capsule, . ,-J; '' 



which, in films stained by 

 ordinary methods, usually 

 appears as an unstained 

 halo, but is sometimes 

 stained more deeply than 

 the ground of the pre- 

 paration. This difference 

 in staining depends, in FIG. 64. Film preparation of pneumonic 

 partat least, ontheamount % utum > Rowing numerous pneumococci 

 L , i - i_-'t (Fraenkel s) with unstained capsules: 



of decolorisation to which ^ ome are ar ' ranged in short chains> F 



the preparation has been Stained with carbol-fuchsiu. x 1000. 

 subjected. The capsule 



is rather broader than the body of the coccus, and has a sharply 

 defined external margin. This organism takes up the basic 

 aniline stains with great readiness, and also retains the stain in 

 Gram's method. It is the organism of by far the most frequent 

 occurrence in true croupous pneumonia, and in fact may be said 

 to be rarely absent. 



(2) Friedldnder 1 s Pneumobacillus. As seen in the sputum 

 and tissues, this organism, both in its appearance and arrange- 

 ment, as also in the presence of a capsule, somewhat resembles 

 Fraenkel's pneumococcus, and it was at first described as the 

 " pneumococcus." The form, however, is more of a short rod- 

 shape, and it has blunt rounded ends ; it is also rather 

 broader than Fraenkel's pneumococcus. It is now classed 

 amongst the bacilli, especially in view of the fact that elongated 



