BACTERIOLOGICAL EXAMINATIONS 107 



Since the early morning sputum coughed up from the lungs is 

 most likely to contain the tubercle bacilli, that should be collected 

 if possible in a wide-mouthed receptacle. In making the examina- 

 tion one of the yellowish white cheesy masses is taken on a sterile 

 platinum loop and smeared on a glass slide. The film is fixed 

 by heat in the usual manner and stained with Ziehl-Neelsen's 

 carbol fuchsin. 



If the bacilli in the sputum are not sufficiently numerous to be 

 detected by the above method they may sometimes be found if 

 a concentration be effected. Antiformin, a patented preparation 

 consisting of sodium hydroxide and sodium hypochlorite, is mixed 

 with the sputum in the proportion of about one sixth antiformin 

 to five sixths sputum ; the mixture is thinned with a little sterile 

 water and centrifuged. The clear upper fluid is removed, more 

 water added to the sediment, and recentrifuged. The upper fluid 

 is again removed, and the sediment smeared on to slides and 

 stained. The antiformin dissolves the sputum and kills most of 

 the bacteria except the tubercle bacilli. 



If negative results are obtained by both of the above methods 

 the search for the tubercle bacilli may be continued by means of 

 animal inoculation. About 2 c.c. of sputum thinned with a little 

 salt solution is injected subcutaneously, preferably in the thigh, 

 into a guinea pig. At the end of four to six weeks the animal will 

 probably die ; if not it is best to kill it by allowing it to inhale ether 

 or chloroform. The animal is autopsied and the peritoneal nodes, 

 the spleen, and the inguinal nodes at the site of inoculation removed. 

 The tissue is cut in small pieces with a sterile knife and forceps. 

 Films are made and portions of the tissue are gently rubbed over the 

 surface of special media. In this way pure cultures may be ob- 

 tained from material containing very few tubercle bacilli although 

 other organisms may be abundant. Growth on artificial media 

 is comparatively slow ; it may not appear on the inoculated tubes 

 before the end of seven or eight days. 



Urine. Specimens of urine for bacteriological examination 

 should be taken by means of a sterile catheter and passed into a 

 sterile container. The urine is centrifuged, the upper fluid poured 



