358 Tuberculosis 



It is said that sections stained in this manner do not 

 fade so quickly as those stained by Ehrlich's method. 



Gram's Method. The tubercle bacillus stains well by 

 Gram's method and by Weigert's modification of it, but 

 these methods are ill adapted for differentiation. They 

 should not be neglected when no tubercle bacilli are demon- 

 strable by the other methods, as they are particularly well 

 adapted to the demonstration of such of the organisms as 

 may not be acid-proof. 



Isolation. The best method of obtaining a culture of 

 the tubercle bacillus from sputum, pus, etc., is to inoculate 

 a guinea-pig, allow artificial tuberculosis to develop, and 

 make cultures from one of the tuberculous lesions. 



The sputum or other tuberculous material used for inocula- 

 tion may be injected beneath the skin with a hypodermic 

 syringe, or placed in a little subcutaneous pocket made by 

 snipping the skin of the abdomen with scissors and dis- 

 secting it loose so that the fragment is easily introduced. 

 As the guinea-pigs are very susceptible to infectious organ- 

 isms of various kinds, their presence is a source of danger. 

 To guard against the premature death of the animals, and 

 the consequent loss of material, a number of animals should 

 be simultaneously inoculated, and great care be exercised 

 to secure tuberculous tissue as free from contamination as 

 possible. The animal is allowed to live for three or four 

 weeks and then killed. The autopsy is performed according 

 to directions already given. An enlarged lymphatic gland 

 with softened contents or a nodule in the spleen is usually 

 selected for the culture. An incision is made into it with 

 a sterile knife, or with a rigid sterile platinum wire, and 

 some of the contents removed and planted upon blood-serum, 

 as recommended by Koch; glycerin agar-agar, as recom- 

 mended by Roux and Nocard; glycerinized potato, as 

 recommended by Nocard; upon coagulated dogs' blood- 

 serum, as recommended by Smith, or upon coagulated egg, 

 as recommended by Dorset. The most certain results 

 follow the employment of the dogs' serum and egg media. 

 The inoculated tubes must be kept in an incubator at the 

 temperature of 37-38 C. 



Piatkowski* suggests that for the cultivation of the 

 tubercle bacillus and other "acid-proof" organisms, advan- 

 tage be taken of their ability to resist the action of for- 



* "Deutsche Med. Wocfrenschrift," June 9, 1904, No. 23, p. 878. 



