96 STUDY AND IDENTIFICATION OF BACTERIA 



4. The cutaneous inoculation method (similar to ordinary vaccina- 

 tion methods). Scarify two small areas on the arm (J^o mcn m diame- 

 ter), about 2 inches apart. Rub in one a drop of old tuberculin, in 

 the other a drop of 25% tuberculin. As a control scarify a spot mid- 

 way and to one side of the others and rub in i drop of 0.5% carbolic 

 glycerine. The appearance of bright red papules in twenty-four hours 

 indicates reaction (von Pirquet). 



It is now recommended to deposit a loopful of undiluted tuberculin on the skin 

 and below that a loopful of saline. A linear incision with a sharp scalpel or glass 

 needle is made through the saline and then through the drop of tuberculin trying not 

 to draw blood. After two to five minutes the tuberculin is wiped off. No dressing is 

 required. Reaction usually appears as induration or inflammatory areola or vesicles 

 after twenty-four hours, but may be delayed forty-eight hours. This is the method 

 of preference. 



5. Intracutaneous inoculation of i drop of a i-iooo, i-ioo or i-io 

 dilution of old tuberculin (Mantoux and Moussu). 



Webb recommends hypodermic needle points which have been dipped in old 

 tuberculin and the points allowed to dry. A drop of water is placed on the skin 

 and the needle points having been moistened in it are plunged through the skin and 

 withdrawn with a twist. A definite lump shows a positive reaction. 



6. Ointment tuberculin test. Rub in 50% ointment of tuberculin 

 in lanolin. Reaction is shown by dermatitis with reddened papules 

 in twenty-four to forty-eight hours (Moro). 



7. Inoculation of bovine and human tuberculin to diagnose type of 

 infection (Detre). Of questionable value. 



Ebright injects the suspected material into the subcutaneous tissue of one side 

 of the abdomen of 3 guinea-pigs. At the end of one week an injection into the 

 other side of the abdomen of one of the guinea-pigs of H c.c. tuberculin is given. 

 Twenty-four hours later smears are made from the original site of inoculation and 

 examined for tubercle bacilli. If negative this is repeated with a second guinea- 

 pig at the end of the second week and finally at the end of the third week with the 

 third guinea-pig. 



Bloch's method is to damage the lymphatic glands in the inguinal region by 

 squeezing the tissue between the fingers. Injections made there of tuberculosis 

 material show abundant tubercle bacilli in these damaged glands in ten to twelve 

 days. 



In staining it is better to use the Ziehl-Neelsen method, decolorizing 

 with 3% hydrochloric acid in 95% alcohol. The alcohol, for all prac- 

 tical purposes, enables us to eliminate the smegma and similar bacilli, 

 these being decolorized by such treatment. There are two objections 





