312 BACTERIA PATHOGENIC TO MAN 



Instead of the Koch-Ehrlich aniline-water solution, Ziehl's carbol- 

 fuchsin solution may be used, and is by many preferred. Instead of 

 floating the cover-glass smears on the staining fluid they can be held 

 in the Cornet forceps, covered and kept covered completely with fluid 

 while steamed for two minutes over the flame. 



The Koch-Ehrlich aniline-water solution decomposes after having 

 been made for a time, so that it must be freshly prepared as needed. 

 Solutions older than fourteen days should not be used. The advan- 

 tages in using Ziehl's carbol-fuchsin solution are that it keeps well 

 and is more convenient for use in small quantities. 



Another method, which is often of value on account of its simplicity 

 and rapidity of performance, is that of Frankel as modified by Gab- 

 bett. This consists in staining the cover-glass "smear" with steaming 

 ZiehPs carbol-fuchsin solution for from one to two minutes, and then, 

 after washing in water, placing it from one-half to one minute directly 

 in a second solution which contains both the acid for decolorizing and 

 the contrast stain. This second solution consists of 



Sulphuric acid 25 c.c. 



Methylene blue in substance ...... 2 grm. 



Water 75 c.c. 



It is then washed with water and is ready for examination. The tubercle 

 bacilli will remain red as stained by the fuchsin, while all the other 

 bacteria will be tinted blue. 



When the number of tubercle bacilli in sputum is very small they 

 may easily escape detection. Methods have, therefore, been suggested 

 for finding them under these circumstances. Ribbert proposed the 

 addition to the sputum of an equal amount or more of a 2 per cent, solu- 

 tion of caustic potash, and boiling the mixture. The mucus is stirred 

 slightly until it is dissolved. To this an equal amount of water is stirred 

 in and the whole is placed in a conical glass vessel; and any bacilli present 

 are deposited at the bottom and may be found in the sediment after 

 removing the supernatant fluid. The sedimentation may be obtained 

 more quickly by the centrifugal machine. 



Detection of Tubercle Bacilli in Urine and Feces. The catheterized 

 urine is centrifuged. If little sediment appears, the upper portion of the 

 fluid is removed and the remainder again centrifuged. If the urine is 

 rich in salts of uric acid, the same may be diminished by carefully warm- 

 ing the urine before treating it. If too alkaline add a little acetic acid. 



The feces are examined for any purulent or mucous particles. If 

 none are found the larger masses of feces are removed and then the rest 

 diluted and centrifugalized. The examiner must remember that bacilli 

 swallowed with the sputum may appear in the feces. 



Examination for Other Bacteria (Mixed Infection). With regard to 

 the bacteriological diagnosis of pulmonary phthisis, many consider that 

 it is not enough to show only the presence of tubercle bacilli; it is held 

 to be of importance, both for purposes of prognosis and treatment, 

 that the presence of other micro-organisms which may be associated 



