432 THE TUBERCLE BACILLUS GROUP 



with water, dry and examine. Acid-fast bacteria are stained red, 

 all other organisms are blue. 



Much Granules. Certain granules are found in old caseous foci 

 and occasionally in the pus of cold abscesses which do not contain 

 tubercle bacilli demonstrable by the acid-fast stain. Material con- 

 taining these granules introduced into guinea-pigs causes a rapidly 

 fatal tuberculosis. Much 1 states that these granules are living frag- 

 ments of tubercle bacilli which develop into the typical bacillus when 

 environmental conditions are optimum. They are Gram-positive and 

 non-acid-fast, but may regain their acid-fastness. When they are 

 non-acid-fast they do not multiply. The exact significance of these 

 granules (Much granules) is as yet undetermined; whether they are 

 identical with the "splinters" described by Spengler 2 is problematical. 

 The "splinters" are usually colored red with fuchsin, and they frequently 

 appear in tubercle bacilli that do not stain uniformly, appearing as 

 rows of red, acid-fast granules. According to Spengler they may be 

 found in sputum or other tuberculous material as heaps of small 

 granules, even if the bacilli themselves cannot be demonstrated. 



Isolation and Culture. It is difficult to cultivate the tubercle bacillus 

 directly from lesions upon artificial media and it is even more diffi- 

 cult to obtain pure cultures directly from sputum, feces, or lung 

 cavities where tubercle bacilli are growing in the presence of other 

 organisms which develop much more rapidly on artificial media. The 

 initial growth on artificial media is the most difficult to obtain. Either 

 coagulated dog's serum 3 or the Dorset egg medium 4 is best for this 

 purpose. Tissue containing tubercles is removed from the animal 

 with aseptic precautions to sterile Petri dishes. The tissue is minced 

 somewhat and then distributed over the slanted surface of either the 

 serum or the egg medium. At the end of a week or ten days the bits 

 of tissue are moved around to fresh surface areas; at the end of two 

 to four weeks the tubercle bacilli appear as minute gray nodules 

 which gradually spread, forming eventually a wrinkled dull gray- 

 yellow growth covering the greater part of the medium. Subcul- 

 tures from the original culture grow better on artificial media than 

 the original culture, although even subcultures grow very slowly. 



1 Beitr. z. Klinik d. Tuberkulose, 1907, viii, 85, 357, 368; 1908, xi, 67; 1913, Supp. 

 Bd. vi. 



2 Deutsch. med. Wchnschr., 1907, p. 337. 



3 Coagulated at 75 C.; Theobald Smith, Jour. Exp. Med, 1898, iii. 647; Trans. 

 Assn. Am. Phys., 1898, xiii, 417. 



4 Bureau of Animal Industry. Annual Report, 1902, p. 574. 



