154 THE MORE CHRONIC INFECTIOUS DISEASES 



Disinfection. To disinfect material from the tuber- 

 culous 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 acid 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, car- 

 bolic acid or lime solution. Feces and urine should be 

 received and well mixed into the same solutions. After 

 death from tuberculosis the room and all contents 

 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 material to be examined 

 is spread on glass slides and stained by a special tech- 

 nic. The tubercle bacillus, because of the presence 

 of waxy and fatty matters in it, stains with difficulty 

 and when once stained cannot be decolorized by acid 

 or alcohol, for this reason being called an acid-fast 

 organism. In order to stain the rod it is customary 

 to use a chemical, called a mordant, to assist the stain- 

 ing material in penetrating; these mordants are usually 

 carbolic acid and anil in oil. The dye is usually fuchsin, 

 imparting a red color to the organisms. After staining, 

 a decolorizing solution is applied to the preparation 

 and all but the tubercle bacilli are destained, leaving 



