20 MEDICAL BACTERIOLOGY 



amined. Those organisms which are only acid-fast, as well as those which are 

 acid-fast and alcohol-fast, appear red, other bacteria blue. 



CARBOL FUCHSIN 



Saturated alcoholic solution of fuchsin, i cc. 



Five per cent, aqueous solution of carbolic acid, 9. cc. 



PAPPENHEIM'S SOLUTION 



Coralin (rosalic acid), i Gm. 

 Absolute alcohol, 100 cc. 



Mix acid and alcohol together; add methylene blue to saturation and 20 cc. 

 of glycerin. 



GABBET'S SOLUTION 



Methylene blue, 2 Gm. 



25 per cent, aqueous solution sulphuric acid, 100 cc. 



The flagella possessed by motile bacilli cannot be demonstrated by any of 

 the methods of staining previously described. Many stains have been devised 

 especially for this purpose; McCrorie's is probably the best. 



McCRORIE'S FLAGELLA STAIN 



Saturated alcoholic solution of night blue, i cc. 



10 per cent, aqueous solution of tannic acid, i cc. 



10 per cent, aqueous solution of alum, i cc. 



Eighteen-hour-old agar cultures are used. Thin spreads are carefully dried 

 at a temperature not greater than 5oC. Apply stain for 2 minutes, then gradu- 

 ally heat until steam rises, wash, dry and examine. 



The demonstration of flagella is difficult and of no practical importance. 



To. stain the capsule with which some organisms are surrounded requires 

 special stains and Muir's method will be found satisfactory. Only very thin 

 films should be made to obtain capsule staining. 



MUIR'S METHOD 



1. Stain with carbol fuchsin for 30 seconds, and steam. 



2. Wash with 95 per cent, alcohol for several seconds. 



3. Wash with water. 



4. Apply mordant for 5 to 10 seconds. 



5. Wash in water. 



6. Wash with alcohol for i minute. 



7. Wash in water. 



8. Counter stain with methylene blue for J^ minute. 



9. Dehydrate in alcohol. 



10. Clear in xylol and mount. 



