50 GENERAL BACTERIOLOGY 



g. Stain witli hot earbol-fuchsin for about one minute. 

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

 Eefeebnces. a. 174 ; H. 100 ; M. & E. 107 ; MeF. 156 ; P. 205. 

 Special Dieections. Stain B. typhosus from ciiltures fur- 

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



EXEKCISE 27. CAPSULE STAIN (Welch). 



General Directions. 



a. Spread film without the use of water. 



h. Air dry. 



c. Fix. 



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

 not wash in water. 



e. Apply Ziehl's earbol-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 Bad. pneumoniae or a milk culture of a 

 capsule bearing organism as Bad. pneum,onicum, (Fried.) Mig. or 

 Bad. capsulatum (Stern.) Chester. 



EXERCISE 28. STAIN FOE METACHROMATIC GRANULES (Erkst). 



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

 with Loeffler 's methylen blue for about 3 minutes. 



h. Wash in water. 



c. Treat with a saturated solution of Bismai;ck brown for 30 sec- 

 onds. 



d. AVash 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 {Sacckaromyces 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. 



