THE EXAMINATION OF MICRO-ORGANISMS 615 



To Find the Diplococcus pneumoniae stain thus: — 



Aqua eosin, twenty seconds. 



Wash, treat with aniline gentian violet, ten minutes. 

 Pour off, treat with Gram's iodine, two minutes. 

 Pour off, blot, and treat with aniline oil until colour ceases to come 

 out freely. 



Treat with xylol to stop the action of aniline oil. 



To Stain Spores. 



Hot carbol fuchsin, five minutes. 



Wash, treat with 20 per cent, acid, two dashes. 



Wash well to get rid of the acid. 



Stain with Loeffler's blue, four to five minutes. 



Wash, dry and mount. 



In examining a micro-organism ascertain its : — 



Motility, morphology, acid-fast or not, Gram-positive or not, does 

 ir form spores or not. 



Remember that no acid-fast organism is motile, 



no coccus is acid-fast or forms spores, 

 all acid-fast organisms are Gram-positive, 

 Gram-negative organisms are non-sporing except 

 the bacilli of malignant oedema. 



Thus a cholera vibrio would be motile, hence it would not be 

 acid-fast nor would it form spores. 



Motility depends upon flagella but the extent of movement does 

 not depend upon the number of flagella. These latter are difficult to 

 stain and readily break off. 



Brownian movement can be performed by inanimate matter as well 

 as by some micro-organisms. 



TO DIAGNOSE MICRO-ORGANISMS. 



One must know their morphology. 



The chief ones from the acid-fast group are : — 



(1) The Tubercle Bacillus. 



A non-motile slender rod with rounded ends, often slightly curved, 

 2'5 to 5 /x long. Some portions do not stain well and hence it often 

 presents a "beaded " appearance. 



It is acid-fast. 



The culture is aerobic and facultatively anaerobic. 



Grows slowly at blood heat. 



In glycerine broth it develops as a floating pellicle. 



On glycerine agar it gives a creamish. dry and wrinkled film. 



It does not liquefy gelatin. 



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