AND SIMILAR PHENOMENA 307 



acquired the power of absorbing haemolytic complements from 

 fresh serum, and so of inhibiting the haemolysis of sensitized red 

 corpuscles. Extracts of normal organs had no such power. 



This is made the basis for their theory of the reaction. The 

 injected tuberculin circulates in the blood until it reaches the 

 antituberculin present in the lesions. The two combine, and in 

 doing so attract the complements which we must suppose to be 

 free in the plasma. This fixation is supposed to be followed by 

 cytolysis of the cells of the part. This accounts for the local 

 reaction. In this solution of the tissue cells products of disintegra- 

 tion are set free, pass into the blood, and give rise to fever, causing 

 the ioeal reaction. Thus neither the jbcal nor the general reaction 

 is due to the direct toxic action of the tuberculin itself. In this 

 the theory approaches somewhat to Marmorek's, and is in funda- 

 mental opposition to the older theories of "addition." 



YVassermann and Briick bring forward an important piece of 

 evidence in favour of their theory by finding antituberculin present 

 in the serum of patients who had been treated with increasing 

 doses of tuberculin and had lost their power of reacting. In them 

 the tuberculin injected would be immediately neutralized in the 

 blood, and so never reach the lesion. The theory is ingenious, 

 and may possibly turn out to be the correct one, but there are 

 difficulties. Thus the authors find tuberculin as well as antituber- 

 culin in the diseased tissues, and it is difficult to see why the two 

 do not neutralize one another. And we might also ask why no 

 digestive phenomena should follow the union of the antituberculin 

 and tuberculin in the blood of injected patients, and the subsequent 

 absorption of the complements. Why should not the proteid 

 molecules be digested, liberate their products, and produce fever ? 

 It would seem that the antituberculin present in the lesion must 

 be in a state of fixation to the cells, or it must be carried away in 

 the blood-stream, and this, according to Wassermann and Briick) 

 rarely happens except after injections. But we do not know 

 definitely of any such antitoxin, the nearest approach to it being a 

 superabundance of suitable sessile receptors, which, if they occurred, 

 might very well make their way into the extracts used in the test, 

 and simulate an antitoxin. And if this were the case, there is no 

 explanation why these receptors are not shed in the normal tuber- 

 culous process, but are after the use of tuberculin. It is difficult, 

 too, to see why the presence of these abnormally numerous 

 receptors might not be made the basis for a " theory of addition " 



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