CUTANEOUS REACTION IN LEPROSY. 325 



The important question to be answered in regard to these reactions is 

 what value have they in the diagnosis of tuberculosis. A rather volumin- 

 ous literature has already appeared with this object in view, which is 

 not surprising when one considers the ease with which the tests may be 

 applied and that every hospital offers material for investigating one phase 

 or another of the question. 



The consensus of opinion with regard to von Pirquet's cutaneous reac- 

 tion seems to be that it is a specific reaction for tuberculosis and hence 

 scientifically and statistically valuable. As an aid to diagnosis, a distinc- 

 tion must be made according as children or adults are being subjected to 

 the test. In children, a positive result indicates that the child is tuber- 

 culous but a negative one does not necessarily mean that the child is 

 free from tuberculosis since only about 50 per cent of the cases of miliary 

 tuberculosis and tuberculous meningitis give the reaction. The test is 

 of distinct value as an aid in diagnosis in children. In adults, since 

 from 50 to 90 per cent of healthy individuals react positively, only the 

 failure to get the reaction can be of service, and its diagnostic value is 

 extremely limited. 



Wolff-Eisner's conjunctival reaction yields approximately the same re- 

 sults as the cutaneous reaction, though he claims that it does not indicate 

 healed foci as does the cutaneous reaction and that therefore it is of 

 more value as an aid to diagnosis in adults. 



The ointment reaction of Moro would seem to give less satisfactory 

 results than the other two. 



It will be remembered that the old subcutaneous injection of Koch's 

 tuberculin was open to the same objections as are encountered in these 

 recent methods : that is, it called forth a reaction in a large percentage 

 of healthy adults and failed to give the reaction in many cases of miliary 

 tuberculosis, tuberculous meningitis and in cachectic individuals. 



If the cutaneous and ophthalmo-reactions should prove to be of equal 

 diagnostic value with Koch's subcutaneous injection, then the latter 

 method would probably cease to be used for diagnostic purposes because 

 (1) of the danger of activating an old tuberculous focus, (2) it caij not be 

 used in patients with fever, (3) it requires that the patient be kept in bed 

 four days, two days for observation before the injection and two days 

 after the injection. 



Attempts have been made to apply the cutaneous and ophthalmo tests 

 to a number of other bacterial diseases. Chantemesse's work on the 

 conjunctival reaction in typhoid fever attracted wide attention, but has 

 not been confirmed by German investigators. However, Meroni * recently 

 has obtained positive results on 25 cases with more than that number 

 of controls. 



'Miinch. med. Woe. (1908), 55-1, 1379. 



