330 A MANUAL OF BACTERIOLOGY 



cutaneously in the abdomen, the other intra-peritoneally. Negative 

 results are nearly as valuable as positive ones. 



In fceces, if definite yellow caseous particles can be found, these 

 should be picked out, and films made and stained. Antiformin 

 may also be used. About 5-6 c.c. of faeces are mixed with 20 c.c. 

 of 15 per cent, aqueous antiformin in a conical glass, well agitated 

 and broken up, and an equal volume of the dilute antiformin is 

 then added. The mixture is allowed to stand for an hour, and films 

 are prepared from the white curdy layer which forms, stained, and 

 examined. 



4. M ilk. See section on milk (Chapter XXI). 



V. The opsonic method. The general mode of carrying this out 

 is described at pp. 314-319, the tubercle bacilli being suspended in 

 1-5 per cent, salt solution. 



VI. Tuberculin reactions. The old tuberculin is used for diagnostic 

 purposes ; it is not perhaps very safe. A dose of 0-0002 c.c. is 

 injected subcutaneously, and the temperature taken four-hourly 

 during the succeeding thirty-six hours. A rise of 2-3 F. or more 

 ensues a few hours after injection in tuberculous subjects. If no 

 reaction occurs another dose of 0-0005 c.c. may be given after the 

 lapse of some days. 



This method has now almost completely been superseded by the 

 cutaneous or by the ophthalmo reaction. 



The cutaneous tuberculin reaction. Von Pirquet 1 discovered that 

 when tuberculin is introduced into the superficial layers of the skin 

 of tuberculous individuals, as in vaccination, a reaction occurs 

 consisting of the formation of a papule with redness, slight swelling 

 and exudation, and sometimes small vesicles. This reaction is 

 usually at its height twenty-four to forty-eight hours after inocula- 

 tion. In healthy individuals no reaction follows the inoculation. 

 The method is to scarify a small spot on the forearm through a drop 

 of a dilution of the old tuberculin, and protect the patch with a 

 simple dry dressing. Moro has modified the method by applying 

 the tuberculin to the skin in the form of ointment. 



The ophthalmo-tuberculin reaction. Calmette transferred the site 

 of inoculation from the skin to the conjunctiva. He makes use of 

 material prepared by precipitating the old tuberculin with alcohol, 

 of which a 1-100 solution is prepared in distilled water. One drop 

 of this is instilled into the inner half of the conjunctiva of one eye. 

 In tuberculous individuals a reaction follows, usually in six to sixteen 

 hours after medication, consisting of a conjunctivitis, ranging in 

 intensity from a local redness to a redness extending over the whole 

 1 Wien. msd. Woch., July 6, 1907. 



