62 CLINICAL BACTERIOLOGY AND H^EMATOLOGY 



ment examined. In some cases in which there is no vomit it is 

 occasionally justifiable to give an emetic for the purpose of 

 securing sputum and establishing the diagnosis. 



Method of Preparation of the Film. 



Sputum. — Pour the sputum into a Petri dish or watch-glass, 

 and place the vessel upon a dark surface. Examine it closely, 

 looking out for small yellow particles ; these consist of caseous 

 material, and will probably contain tubercle bacilli in large 

 numbers. The advantage of getting the patient to wash out his 

 mouth and using only fasting sputum is obvious, for particles of 

 food may present exactly the same appearance. 



Having found such a mass, pick it out by means of a platinum 

 loop or pair of forceps, and transfer it to the middle of a clean 

 slide. Now place another slide on the top of the first, squeeze 

 them together, and then slide them apart. You should get two 

 good uniform films. Allow to dry spontaneously, 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 occasional shake during 

 the next few hours. 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. 



Another method which may be used in difficult cases is to 

 digest the sputum with pepsin and HCl— 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 occasionally, and then to 

 boil the digested material to prevent further action. The result 

 may be centrifugalized or allowed to deposit, and the sediment 

 examined. 



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. 



