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TUBERCULIN IN DIAGNOSIS 327 



By gradually increasing the dose of tuberculin a non-specific reaction can 

 [it is said] be produced in healthy persons. [But] in any case it would be 

 most unwise to inoculate such dangerous doses. 



3. Repeated inoculation of small doses. Many observers advise that four 

 five small doses, O1-O2 mg., should be given at intervals of 3 or 4 days. 



is the least dangerous method and the one to be adopted to avoid the 

 toward results which so frequently follow the inoculation of tuberculin. 

 Repeated small doses lead to a state of hypersensibility l and the diagnosis 

 can be made without running the risks attendant upon the use of increasing 

 doses. About 95 out of every 100 tuberculous subjects react to the third 

 or fourth inoculation. 



When several successive inoculations of tuberculin are made signs of inflammation 

 appear after each fresh injection around the sites of the former inoculations. The 

 lesions produced are similar to those set up [in the early stages of an infection] by 

 the tubercle bacillus (Klingmueller). 



4. Cuti-reaction. Von Pirquet has shown that when tuberculin is inocu- 

 lated through scratches on the skin of a tuberculous child, in nearly every 

 case (save in acute miliary tuberculosis and tuberculous meningitis) a small 

 papule occasionally a vesicle appears lasting about 8 days ; at first it is 

 bright red but subsequently becomes darker in colour. This reaction is of 

 great diagnostic value in the early years of life. Older children -often, and 

 adults nearly always, react even when tuberculosis cannot be demonstrated 

 clinically (which calls to mind the fact that post mortem nearly all adults show 

 lesions of tuberculosis). In cachectic individuals the reaction often fails. 



To effect the reaction make four small scarifications, not deep enough to draw 

 blood, on the skin of the outer and upper part of the arm and cover the lower three 

 with a small drop of diluted tuberculin (p. 326). (Tubes containing tuberculin for 

 the cuti-reaction can be purchased at the shops.) The vaccination marks should 

 be about 2 cm. apart. The upper mark which has not been treated with tuberculin 

 serves as a control. When the reaction is positive, a swelling begins to appear 

 about 48 hours after inoculation. 



H. Vallee has shown that von Pirquet's cuti-reaction is of value as a 

 diagnostic test for tuberculosis in the lower animals (cattle, horses and 

 guinea-pigs). While healthy animals do not react, tuberculous animals 

 show, about 36-48 hours after the inoculation, an oedematous infiltration 

 of the vaccination mark with a painful grey-red swelling. The reaction 

 occurs in healthy animals which have been previously treated with a sub- 

 cutaneous inoculation of tuberculin (this confirms Klingmueller's phenomenon 

 described above). 



5. Intra-dermo reaction. This method of diagnosis is recommended by 

 Martoux but does not seem to offer any advantages over the cuti-reaction. 

 The reaction consists in inoculating a drop of tuberculin into the skin with a 

 fine needle. Calmette advises a 1 in 5000 solution of dry tuberculin preci- 

 pitated with alcohol. In persons affected with tuberculosis a red, or bright 

 pink, cedematous infiltration surrounded by a more or less extensive area of 

 erythema is seen about 24 hours after the inoculation. 



6. Ophthalmo-reaction. Calmette and Wolff-Eisner have shown that the 

 instillation of a small amount of tuberculin into the eye produces in persons 

 affected with tuberculosis a very marked congestion of the palpebral conjunc- 

 tiva. The test is easily performed and is very delicate and, provided it is 

 not used when any lesion of the eye is present nor in old people, is quite free 

 from danger. 



[ x Repeated injections of large doses sometimes diminish the reacting power of the 

 tissues in animals.] 



