220 BACTERIA 



other acid-fasts several method are now employed. The material 

 to be examined may be stained in the ordinary manner and then 

 decolorized by Pappenheim solution or a saturated solution of 

 methylene blue in absolute alcohol. Preparations should be dried 

 thoroughly before using such solutions. For " enriching" in 

 organisms, the bulk of material, e.g., sputum, is suspended in 15 

 percent antiformin (the proprietary name for a mixture of Javelle 

 water and caustic soda), allowed to stand in the incubator for a 

 while and the suspension centrifuged. In the sediment many 

 more bacilli will be found than in the same bulk of the raw speci- 

 men. This antiformin seems to dissolve mucus, tissue and all 

 bacteria except tubercle bacilli. The method can be used to 

 procure cultures. 



Even with this method organisms escape detection in some 

 certainly tuberculous lesions. This is said to be due to non-acid- 

 fast, but Gram-staining granules. They are said to be found by 

 a-modified Gram-Weigert staining, according to Much. Such 

 specimens should always be injected into guinea pigs for 

 corroboration. 



Immunity. It is possible to immunize cattle against virulent 

 bovine tubercle bacilli by inoculating them previously with a cul- 

 ture of human tubercle bacilli that have been grown for some , 

 time on culture media, and thus attenuated. The tuberculins, J; 

 if injected into a person with chronic tuberculosis, stimulate the 

 tissues to a slightly greater resistance to the disease. Thus far 

 anti-tuberculous sera are not of a pronounced or certain thera- 

 peutic value. By immunizing horses, Maragliano obtained a 

 serum that he claims is effective. The milk from immunized 

 cattle is used as a diet in tuberculous patients by him. The vari 

 ous tuberculins, some containing endo-toxins, or plasmins, in 

 solution, are capable of stimulating the formation of agglutinins in 

 the sera of man and animals. Blood from infected individuals 

 also contains these bodies. The agglutination test does not seem 

 to be of great practical diagnostic value, while the complement 



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