50 GENERAL BACTERIOLOGY 



g. Stain with hot carbol-fuchsin for about one minute. 

 h. Wash in water, dry and mount in balsam. 

 KEFEBENCES. A. 174 ; H. 100 ; M. & R. 107 ; McF. 156 ; P. 205. 

 SPECIAL DIRECTIONS. Stain B. typhosus from cultures fur- 

 nished, also try B. coli and B. subtilis. 



EXERCISE 27. CAPSULE STAIN (WELCH). 

 GENERAL DIRECTIONS. 

 a. Spread film without the use of water, 

 fc. Air dry. 



c. Fix. 



d. Apply glacial acetic acid, and drain it off immediately. Do 

 not wash in water. 



e. Apply Ziehl's carbol-fuchsin which is to be renewed several 

 times to remove acid. 



/. Wash in 1 to 2% salt solution. 



g. Examine in salt solution. (Balsam causes capsule to shrink). 



REFERENCES. A. 170 ; H. 97 ; M. & R. 106 ; McF. 291 ; P. 203 ; 

 P. B. C. 13. 



SPECIAL DIRECTIONS. Use pneumonic ("rusty") sputum, blood 

 of rabbit infected with the Bact. pneumoniae or a milk culture of a 

 capsule bearing organism as Bact. pneumonicum (Fried.) Mig. or 

 Bact. capsulatum (Stern.) Chester. 



EXERCISE 28. STAIN FOR MET ACHROMATIC GRANULES (ERNST). 



a. Stain a young culture of an organism such as Bact. diphtheriae 

 with Loeffler 's methylen blue for about 3 minutes. 



b. Wash in water. 



o. Treat with a saturated solution of Bismarck brown for 30 sec- 

 onds. 



d. Wash in water, mount in water and examine, or, dry, mount 

 in balsam and then examine. 



The granules should appear blue in a brown organism. 



EXERCISE 29. MORPHOLOGY OF YEASTS AND MOULDS COMPARED 



WITH BACTERIA. 



a. Mount some baker's yeast (Sac char omyces cerevisiae) and 

 examine in an unstained condition. Compare: Size; form; struc- 

 ture and method of reproduction with the bacteria. 



~b. In same way examine a number of common moulds, e. g. 

 Mucor, Penicillium and Aspergillus. 



