208 INFLAMMATORY AND SUPPURATIVE CONDITIONS. 



(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 solu- 

 tion of methylene-blue, but 

 Gram's method is to be pre- 

 ferred, with safranin or Bis- 

 marck-brown as a contrast 

 stain. Ziehl-Neelsen carbol- 

 fuchsin is also very suitable; 

 it is best either to stain with 

 it for only a few seconds, or 

 to overstain and then decol- 

 orise with alcohol till the 

 ground of the preparation is 



FIG. 77. Film preparation of pneumonic just tinted. The Capsules Can 



sputum, showing numerous pneumococci , . _, , , +-V, A 1 



(Fraenkel's) with unstained capsules; some be Stained by the metnOQS al- 



are arranged in short chains. Stained with ready described (p. IO6). In 



carbol-fuchsin. x icoo. 



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. 



( i ) FraenkeVs Pnenmococcns. This organism occurs in the 

 form of a small oval coccus, about I /JL in longest diameter, 

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

 four to ten (Fig. 77). The free ends are often pointed like 

 a lancet, hence the term diplococcus lanceolalns has also been 

 applied to it. These cocci 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 in staining depends, 

 in part at least, on the amount of decolorisation to which the 

 preparation has been 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. 



