LESSON xii STAINING OF COCCI IN TISSUES 51 



(3) Stain frozen sections of the following tissues : 



(a) Pysemic abscesses in cardiac muscle and kidney 

 (Staphylococci from a case of ulcerative endocarditis). 



Use Loffler's methylene-blue, or Gram's method. 



Place some sections in the cosine methylene-blue 

 mixture (Czinzinski's solution) over night. 



* (b) Erysipelatous skin. 



Use Gram's method, with or without previous picro- 

 carmine staining. 



(c) Spleen from a case of pyaemia (Streptococcus). 

 Use Gram's method without counterstaining. 



(d) Croupous pneumonia (lung). 



Use Gram's method with or without previous picro- 

 carmine staining. 



(e) Lung of mouse dead of infection with the Micro- 

 coccus tetragonus. 



Stain with the cosine methylene-blue mixture. 



In all these cases, whenever Gram's method is used, 

 leave the section in the stain for twenty to thirty minutes, 

 and be careful not to decolourise too much with the alcohol 

 and acid alcohol (vide p. 45). 



(4) Fibrin staining in croupous pneumonia (Weigert's method). 



To bring out the fibrin network in croupous pneumonia, 

 the following method should be used : 



(a) Place the section on the slide by means of a cigarette- 

 paper. 



