EHRLICH S SIDE CHAIN THEORY. 147 



The antibodies against toxins and ferments are of the simplest form. They possess 

 only a binding group which has an affinity toward the haptophore group of the toxins 

 and ferments. They, therefore, belong to the class designated by Ehrlich as "hap- 

 tines" of the first order. 



To the haptines of the second order belong the agglutinins and precinitins. They 

 possess besides a haptophore group also an agglutinophore or percipitinophore group 

 by virtue of which agglutination or precipitation takes place. 



Belonging to the haptines of the third order are the class of amboceptors which have 

 in addition to the haptophore group also a complementophile group for their union 

 with the complement. 



These hypotheses of Ehrlich greatly simplify the explanation of many serum eactions 

 as well as many of the phenomena associated with the action of tuberculin. In all 

 probability the healthy cells which exist in the tuberculous focus and which are capable 

 of reaction, produce the antituberculin. Christian and Rosenblatt offered experimental 

 evidences for this statement. They demonstrated that tuberculous guinea-pigs in whom 

 antituberculin was produced by tuberculin injections, showed a diminution of anti- 

 tuberculin in the blood when tuberculous glands were removed by operation. 



The antituberculin production by the cells is a transitory action arising only when 

 tuberculin has spontaneously or artificially reached the circulation. Following this 

 stage of activity there comes a period of quiescence during which no free antituberculin 

 can be found in the serum. The cells, however, are supplied with a great many more 

 sessile receptors than usually; they possess a higher affinity toward tuberculin and 

 produce antituberculin much more readily than normal cells. 



This also explains why the smallest amounts of tuberculin produce a reaction in 

 tuberculous and not in the normal individuals. In the former, the cells in the zone 

 surrounding the tuberculous focus are abundantly supplied with receptors, so that on 

 the injection of tuberculin, its action appears almost concentrated at this point. Occa- 

 sionally the sessile receptors are relatively scarce and the first injection excites no 

 reaction. ' By the time of the second or third inoculation these sessile amboceptors 

 have so increased that a positive reaction is apparent when the same or even a smaller 

 dose is injected. This phenomenon of increased sessile receptors explains the reappear- 

 ance of subsided, subcutaneous, cutaneous, or ophthalmo reactions after renewed 

 injections of tuberculin. 



To recapitulate the biological phenomena associated with a positive 

 tuberculin reaction, it may be said that the tubercle bacilli, or portions of 

 their body substances existing in the infected focus, stimulate the adjacent 

 cells to produce a great number of sessile receptors. When the tuberculin 

 is injected for the first time, these sessile receptors at once take up the tuber- 

 culin and as a result, the production of antituberculin in the focus is further 

 stimulated. Every production of antibodies, is, if the stimulant be strong 

 enough, associated with fever; in this very regard, however, Wright as well as 

 Pfeiffer and Friedberger showed that if the smallest doses of antigen are 

 employed, antibody production continues without any rise in temperature. 

 Fever in a tuberculin reaction is therefore not a necessary manifestation of a 

 positive tuberculin reaction, although it generally is present. The enlarged 

 number of sessile antituberculin receptors augments the affinity of the cells 

 toward the tuberculin, and the second, third and succeeding inoculations 

 bring about a focal reaction (i.e., antituberculin production) much more 



