BAUMGARTEN'S METHOD 215 



Gibbes gave the following recipe : 2 grms. fuchsine and 

 1 grm. methyl blue are slowly introduced into a solution 

 of 3 c.cm. aniline oil in 15 c.cm. absolute alcohol untU they 

 are completely dissolved, and 15 c.cm. water are then 

 added. A few drops of this liquid are heated in a test-tube 

 and poured out into a watch-glass, in which the cover-glass 

 is laid for five minutes, being then washed in alcohol until 

 no more colour is discharged. The bacilli are red on a 

 blue ground. Further staining may be well done with a 

 concentrated aqueous solution of eosine. 



Occasionally it is of advantage to subject the cover-glass 

 preparations to different methods of examination. Kaatzer 

 recommends staining the same preparations first with 

 carbolic fuchsine after the Ziehl-Neelsen or B. Prankel's 

 method, and examining them with the oil immersion lens, 

 after which the cedar oil should be removed with blotting- 

 paper and alcohol, the preparation dried in the flame, 

 stained in hot aniline water gentian violet, decolorised in 

 hydrochloric acid and alcohol, and double-stained in vesu- 

 vine. The tubercle bacilli, which were red when first 

 examined, are turned dark violet on a light-brown ground 

 by the second staining. 



In cases where staining yields doubtful results, the pro- 

 cess of Baumgarten may be employed as a control observa- 

 tion. The preparation of sputum, having been dried in 

 air and passed three times through the flame, is first laid 

 for a few minutes in a watch-glass containing chloroform 

 to free it from fat, rinsed in absolute alcohol, and, after this 

 has evaporated, is placed on a slide in a drop of potash 

 solution, prepared by adding two or three drops of a 33 

 per cent, solution of caustic potash to a watch-glass of 

 water. If the microscopic examination (without oil im- 

 mersion) reveals the presence of bacilli, the cover-glass 

 is removed from the slide, dried in the air, passed three 



