7O CLINICAL BACTERIOLOGY AND H^MATOLOGY 



first, squeeze them together, and then slide them apart. You 

 should get two good uniform films. Allow to dry spon- 

 taneously, and fix by heat. If there are no caseous masses, 

 pick out a mass of the sputum at random and proceed as 

 before. 



If no bacilli are found at the first examination, and you still 

 suspect tubercle, proceed as follows : Half fill an ordinary 

 medicine bottle with carbolic lotion (i in 20), and add a 

 drachm or two of the sputum. Shake thoroughly for a few 

 minutes, and place the bottle where you can give it an occa- 

 sional shake during the next few hours, or centrifugalize it. 

 Then pour the milky emulsion which results into a conical 

 urine-glass, and allow it to stand for twelve hours or more. 

 Remove some of the deposit which will form with a pipette, 

 and spread it into a thin film on a slide. Dry and fix. The 

 advantage of this method is that the mucin and albuminous 

 materials in the sputum are coagulated and broken up into 

 fine granules by the shaking, and bacilli which occur in small 

 clumps are evenly distributed throughout the filniw 



Another method which may be used in difficult cases is to 

 digest the sputum with pepsin and HC1 a pinch of the 

 former and sufficient of the latter to make the fluid faintly 

 acid in an incubator for a couple of hours, shaking occasion- 

 ally, and then to boil the digested material to prevent fur- 

 ther action. The result may be centrifugalized or allowed to 

 deposit, and the sediment examined. A more recent method 

 is the use of " antiformin," a solution of bleaching powder and 

 caustic alkali. This dissolves all the structures likely to be 

 present in the sputum, except tubercle bacilli. I do not think 

 its use is advisable in ordinary cases. 



Urine may be centrifugalized or allowed to stand without 

 previous addition, but better results are obtained if carbolic 

 acid (liquefied or in crystals) is added to the urine in amount 

 sufficient to convert it into a i in 20 solution. This is allowed 

 to deposit or (better) is centrifugalized. Films are prepared 

 from the deposit. 



Remember that they should be left in alcohol for a quarter 

 of an hour or so after staining. 



Pus is best carbolized in the same way as sputum; if very 

 thin it may be treated like urine. The tubercle bacilli will 

 rarely be found in pus unless it is examined soon after the 



