BACTERIUM TUBERCULOSIS 143 



Disinfection. To disinfect material from the tubercu- 

 lous individual it is necessary to collect it in some 

 manner, permitting burning or the action of chemicals 

 over a long time. Tuberculous sputum is best received 

 in cardboard boxes inclosed in a tin cup. The boxes 

 are burned, and the tin cup washed in 5 per cent, car- 

 bolic acid at frequent intervals. If the person expec- 

 torate into cloths they should be burned or soaked in 

 5 per cent, carbolic for at least six hours. If neither 

 of these methods is used expectoration should be 

 received in a bowl or pot containing 5 per cent, carbolic 

 acid. Feces and urine should be received and well mixed 

 into the same solution. Milk, unless it is known to 

 come from a non-tuberculous cow, should not be used. 

 After death from tuberculosis the room and all con- 

 tents should be disinfected with formaldehyde gas. 



Diagnosis. The most important means of diag- 

 nosis is by finding the tubercle bacillus. To do 

 this, the sputum, urine, feces, pus, exudate, or a 

 piece of tissue is taken, stained by special methods, 

 or injected into guinea-pigs. The method employed 

 for staining these bacteria consists in using a dye 

 having an affinity for the peculiar waxy character of 

 the germ and not easily removed by acids after it has 

 once penetrated it. The bacteria are called acid-fast 

 for this reason. The stain consists of carbolic acid 

 and fuchsin. The former helps the latter to penetrate 

 the germ. We make smears upon slides, stain them 

 by this solution, treat them with an acid which will 

 decolorize everything but the tubercle bacillus. This 

 will show us red bacilli. 



Sometimes the germs are present, but cannot be 



