TUBERCULOSIS. 215 



clean conical glasses and measured therein. The pro- 

 portion of muco-purulent to fluid matter was noted. 

 Depending upon the degree of viscidity and number of 

 bacilli present in the sputum, a varying amount of 5 per 

 cent, caustic potash solution was added to it (from one- 

 sixth to an equal volume), and after the caustic potash 

 had rendered the sputum perfectly fluid more or less water 

 was added to dilute the mixture. The sputum, having 

 been measured, was poured into a perfectly clean wide- 

 mouthed bottle containing fine sterilized gravel or broken 

 glass. Rinsings of a measured amount of the caustic pot- 

 ash solution were used to free the conical glass from what 

 matter might remain and were added to the sputum. 

 The contents of the bottle were agitated in a shaking 

 machine for five minutes, and allowed to stand until the 

 caustic potash solution had had time to act. As soon as 

 the sputum had become homogeneous an equal volume 

 of water was added, and the whole shaken again. The 

 sputum thus treated was of a pale-green or yellowish- 

 brown color, and contained only small fragments of elas- 

 tic tissue. It was allowed to stand two to four hours, 

 and then shaken again for five to ten minutes. 



By means of a burette of original design drops of ex- 

 actly equal size were secured and caught upon clean 

 sterile cover-glasses. The drops were subsequently 

 spread into an even film by a very fine platinum wire, 

 while the cover-glass was rotated upon a "turn-table." 

 After spreading, the cover-glasses were laid upon a level 

 brass plate slightly warmed to facilitate drying. After 

 drying, the cover-glasses were coated with a serum film 

 by spraying, and the temperature raised to 8o-9O C. to 

 coagulate the serum and retain the bacteria in place, 

 after which they were carefully stained with carbol- 

 fuchsin and decolorized with a solution of 150 parts of 

 water, 50 parts of alcohol, and 20-30 drops of pure sul- 

 phuric acid. Prior to this the cover-glass was washed in 

 three alcohols and subsequently in water, and if necessary 

 in acid and alcohol again. 



