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Exercise 36. The Bacteriology of Tuberculosis 
MATERIALS: 
Musuem specimens of tuberculous tissues 
Sputum contain Mycobacterium tuberculosis 
Fresh tuberculous tissues 
Acid alcohol 
1. Examine and describe the specimens of tuberculous tissues in the labor¬ 
atory. 
2. Make a uniform smear of some tuberculous sputum on a clean slide. Air 
dry and fix with gentle heat. 
3. Stain the smear with hot carbol fuchsin for five minutes by placing the 
slide in a tube of the stain heated by boiling water. Wash off under the tap all 
of the stain that will come off. Decolorize the preparations in acid alcohol 
(80 per cent alcohol with 3 per cent nitric acid) until the alcohol that runs from 
the slides is no longer tinged with red. Wash in tap water. Stain the prepa¬ 
rations one to three minutes with methylene blue. Wash in tap water. Dry 
and examine with the oil-immersion objective. The organisms will appear as 
very small red rods on a blue background. If the preparation is not satis¬ 
factory, repeat until a good one is obtained. 
4. Examine tuberculous animals and prepare two smears on clean slides 
from tuberculous glands, liver or spleen. Grasp the tuberculous material in a 
pair of dissecting forceps and carefully grind, crush and smear it over the 
center of the slide. Dry the smear in the air and fix it in the usual manner. 
Stain in the same way as with sputum. 
5. Draw a good field from each preparation, showing the organism and the 
surrounding tissue materials. Describe the organisms and note especially 
their size and shape. 
(a) What is meant by an “acid fast” organism? 
(b) Name some other acid-fast organisms besides the tubercle 
organism. 
(c) Where may they be found? 
( d ) What parts of the body are most often affected in the case of 
tuberculosis of the cow? 
( e ) What parts of the body may be affected? 
(/) What is meant by a calcified tubercle? 
( g ) What is meant by open tuberculosis? 
( h) What is meant by closed tuberculosis? 
(0 How may the disease be acquired by cattle? 
(j) How may it be acquired by hogs? 
