TECHNIQUE OF REACTION. 49 



obtained and occasionally, also a general reaction. The marked severity of the reaction, 

 however, and its apparent lack of specificity, made its diagnostic value improbable." 

 Calmette, who believed that Wolff- Eisner's failure in obtaining authentic results lay in 

 the fact that glycerin was contained in the old tuberculin employed by him, went to 

 work and by alcohol precipitation obtained a glycerin-free dry product, which he used 

 in a i per cent, solution equivalent to 10 per cent, old tuberculin. It was he, therefore, 

 who first established the clinical diagnostic value of the reaction. But his hypothesis 

 was erroneous, as the mild reactions which he obtained were not due to the absence of 

 glycerin, but because the Lille tuberculin made use of is much weaker than trie German 

 preparation. The author was able to show that the old tuberculin could very well be 

 used for the Ophthalmo reaction if instead of the 10, a i per cent, dilution was made. 

 Thus employed, the reaction is exceedingly mild and specific. Eppenstein later advised 

 a 2 and 4 per cent, dilution in cases where the i per cent, solution gave no reaction. 



Technique of Reaction. 



It is of extreme importance to have freshly prepared sterile dilutions of 

 the old tuberculin (Hochst Farbwerke). All the ready-for-use preparations 

 on the market should be discarded. This applies also to the " Tuberculin Test" 

 Calmette' *s sold by Poulenc Freres. 



The mishaps and low grade of specificity often ascribed in literature to 

 the ophthalmo reaction can in a greater majority of cases be explained by the 

 employment of preparations other than the 

 i to 2 per cent, fresh dilutions of the old 

 tuberculin advocated by the author, and in 

 still another number of cases to its employ- 

 ment in conditions where it was distinctly 

 contraindicated. The preparation of fresh 

 tuberculin dilutions is very much simplified 

 by the " Qphthalmodiagnosticum for Tuber- 

 culosis" of the firm P. Altmann, Berlin 

 N. W. 6 (Fig. 14). 



This outfit consists of twelve sealed glass 

 tubes each containing o.i c.c. old tuberculin; 

 a cylinder for the dilution graduated in per- FlG - I 4-~ Ophthalmodiagnosticum for 



tuberculosis. (After Citron.') 



centages, and a measuring pipette o.i c.c. 



in size fitted with a rubber bulb. One of the sealed ampoules is shaken 

 so that the tuberculin is collected into its broader part and then broken at 

 the designated point near the narrow end. The tuberculin is drawn up to 

 the mark into the pipette and then transferred into the cylinder. Boiled 

 water or sterile saline is added to the i, 2 or 4 per cent, dilution mark. 

 The pipette is washed clean in the solution by successive aspiration and 

 expulsion in order to free it completely of the remaining concentrated 

 tuberculin, and can now be employed as the eye dropper. 



The solution should be used only on the day it is prepared. The tuber- 



' 



