PYOGENIC GROUP 77 



a milk-culture of Mkr. lanceolatus. Two methods may 

 be applied for this stain: 



First method (Friedlander's method) : 



a) Prepare a stain by the following formula: 



Glacial acetic acid i part 



Saturated alcoholic solution of gentian- 

 violet 5 parts 



Distilled water 10 parts 



V) Prepare a very thin film in the usual manner from 

 a 24-hour-old milk-culture, taking care to spread very 

 thinly. 



c) Cover with stain for 10-15 seconds. 



d) Wash in a solution of sodium chlorid (0.85 per 

 cent.). 



e) Examine in a sodium chlorid solution. 



/) If satisfactory, float the cover-slip off with salt 

 solution, dry, and mount in balsam. Under no conditions 

 should plain water come in contact with this preparation 

 at any stage; otherwise no capsules will appear. 



Second method (Welch's method) : 



a) Prepare a very thin film in the usual manner from 

 a 24-hour-old milk-culture. 



h) Cover with glacial acetic acid for 5 seconds. 



c) Wash acid off with carbol-fuchsin. 



d) Wash stain off with a 0.85 per cent, sodium 

 chlorid solution. 



c) Examine in salt solution. 



/) If satisfactory, mount in balsam. 



Plain water should not come in contact with this 

 preparation at any stage. The capsule should be ob- 

 served as a lightly stained zone with well-defined outline 

 around the deeply stained organism. 



