400 A MANUAL OF BACTERIOLOGY 



The ophthalmo tuberculin reaction. This method was intro- 

 duced by Calmette. The inoculating material is prepared by 

 precipitating the old tuberculin with alcohol, and a 1100 solution 

 of the deposit is prepared in distilled water. One drop of this is 

 instilled into the inner half of the conjunctiva of one eye. The 

 reaction usually occurs six to sixteen hours after medication, and 

 appears as a conjunctivitis, ranging from a slight and local red- 

 ness up to a severe general conjunctivitis. The inflammation 

 usually soon passes off without ill-effect, but occasionally is 

 severe and even dangerous. On the whole the reaction appears 

 to be fairly constant in tuberculous individuals, but absence of 

 reaction is not certain proof that the case is not tuberculous. 



VII. Tuberculin for veterinary use. The dose of the various 

 preparations in the market varies according to their strength ; it 

 corresponds to 0-1 c.c. or 0-2 c.c. of Koch's original tuberculin. 



The appropriate dose is injected subcutaneously in the neck, 

 and the reaction consists of a rise of temperature of from 1-5 to 

 6 F. above the average normal, commencing eight to twelve 

 hours after injection and lasting twelve to fourteen hours, the 

 temperature being taken at the twentieth hour after injection, 

 or, if it can be done, at frequent intervals from the twelfth to the 

 twentieth hour. The temperature should be taken just before 

 inoculation, and, if possible, morning and evening for two or three 

 days previous to inoculation. 



A healthy animal is unaffected by the injection, and if an 

 animal be extensively affected with tuberculosis the reaction may 

 not be given, or may be masked by the fever present. 



An ophthalmo reaction may also be employed in cattle. 



Johne's disease, 1 a bovine enteritis, is due to an acid-fast 

 bacillus closely resembling the tubercle bacillus in morphology. 

 It is found in scrapings of the affected mucous membrane of the 

 bowel, and also in sections of the intestinal wall. The Johne 

 bacillus is inoculable into the goat, but not into the guinea-pig or 

 rabbit, and does not grow on any of the ordinary laboratory media. 

 Twort states that it can be cultivated on the medium employed 

 by him for growing the leprosy bacillus (p. 404), and from the 

 cultures a diagnostic vaccine may be prepared. 2 



1 McFadyean, Journ. Comp. Path, and Therap., vol. xx, 1907, p. 48. 



2 Twort, Veterinary Record, Sept. 14, 1912. 



