TUBERCULOSIS 125 



4. Counter-stain in solution methylene hhie for three 

 minutes. 



5. Wash slightly, then soak in absolute alcohol for two 

 minutes. 



6. Clear in xylol or oil of cloves. 



7. Transfer to glass slip u-ith a section-lifter, hloi with filter- 

 paper, and mount in xylol balsam. 



By this method the bacilli are seen as bright-red slender 

 rods, which are on the average about three-quarters the 

 diameter of a blood corpuscle. The blue counter-staining is 

 not absolutely necessary, but it throws the bacilli into 

 greater relief. Eibberts has proposed a method of reducing 

 the troublesome viscous character of tuberculous sputum 

 by a short boiling with a 2 per cent, solution of caustic 

 potash. This process has yielded satisfactory results in 

 our hands. 



It must be remembered that the bacilli in the sputum in 

 cases of incipient tuberculosis are often few and far between, 

 so that till ten or a dozen slides have been made and carefully 

 examined, we cannot safely assert that the bacillus is absent. 



Pastor's Cultivation Method. — A gelatine tube is inoculated 

 with a fragment of a caseous particle, or, failing this, with 

 some sputum, well shaken and poured into a plate. 



After three or four days all the organisms except the 

 tubercle will have developed sufficiently to render them 

 visible ; when this has taken place, some of the clear spaces 

 of gelatine between the colonies are cut out and melted on 

 the surface of a glycerine-agar plate and incubated ; if 

 after twenty-one days no colonies appear, the tubercle is 

 not present. 



Some observers consider it worth while to attempt a rough 

 estimation of the number of bacilli present in sputum, with 

 a view of forming an opinion as to the rapidity with which 

 ;the caseous degeneration is proceeding. 



