808 



SCIENCE. 



[N. S. Vol. XVI. No. 413. 



are intermediary body, immune body, am- 

 l)oceptor, sensitizer, fixative, preparative, 

 desmon, and for the other body comple- 

 ment, alexin, cytase. It is this latter body 

 which contains the atomic group described 

 as toxophoric or zjonophorie. 



Concerning the source, mode of action 

 and constitution of the specific antagonistic 

 bodies we are very imperfectly informed. 

 That they are of cellular origin seems cer- 

 tain, and Bhrlich with great ingenuity, on 

 the basis of a brilliant series of experi- 

 ments, has advanced a hyijothesis regard- 

 ing them which, in my opinion, better than 

 any other mtherto suggested, accords with 

 the knoivn facts, and in promoting discov- 

 ery has already done the greatest service 

 of which a working hypothesis is capable. 

 Ehrlich has so recently and so fully in the 

 Croonian lecture presented before English 

 i*eaders his hypothesis of the side chains or 

 leceptors and the basis for it, that I need 

 only recall to your minds his conception 

 that the toxins, cells and other substances 

 which lead within the living body to the 

 production of antitoxins, cytolysins and 

 other antagonists have this capacity only 

 through the possession of specific affinities, 

 called haptophore groups, for correspond- 

 ing haptophore groups belonging to side 

 «hains or receptors of certain cellular con- 

 stituents of the body, and that in conse- 

 quence of this appropriation of receptors, 

 others of like nature are reproduced in 

 •excess of the needs of the cell, and these 

 being shed into the lymph and blood, there 

 constitute the antitoxins, intermediary 

 bodies, agglutinins and other specific an- 

 tagonists. The antitoxic receptor has only 

 a single combining affinity, which is for the 

 toxin, whereas the cast-off receptors consti- 

 tuting the intermediary bodies of cytoly- 

 sins have at least two affinities (hence 

 called amboceptors by Ehrlich), one of a 

 moTC highly specialized nature being for 



the invading bacteria or other foreign cells, 

 and the other for the complement.* The 

 antibody enters quantitatively into definite 

 chemical union with its affinitive substance. 

 The essence of Ehrlich 's theory concerning 

 antitoxin is thus tersely expressed by Behr- 

 ing: 'The same substance which, when in- 

 corporated in the cells of the living body, 

 is the prerequisite and condition for an 

 intoxication becomes the means of cure 

 when it exists in the circulating blood.' 

 So of the twofold bactericidal and cyto- 

 lytic agents we may say that the living 

 body possesses substances which may pro- 

 tect it by destruction of invaders or may 

 injure it by destruction of its own ceUs, 

 according to the mates with which these 

 substances are joined. 



An inquiry which naturally arises in this 

 connection is : What is the physiological 

 mechanism called into action in the pro- 

 cesses resulting in the prodiiction of anti- 

 toxins, cytolysins and similar bodies ? We 

 have no reason to suppose that the animal 

 body is endowed with properties specially 

 designed to meet pathological emergencies. 

 Its sole weapons of defense, often lament- 

 ably imperfect for morbid states, are 



* According to Ehrlicli's latest conception, re- 

 sulting from investigations to demonstrate the 

 multiplicity of complements, an amboceptor has 

 a single cytophilic affinity, and a number of eom- 

 plementophilic affinities differing in their avidity 

 for various complements. He regards the agglu- 

 tinins, precipitins and coagulins as uniceptors of 

 more complex structure than the antitoxins, but 

 Bail has recently brought evidence to show that 

 agglutinins, like cytolysins, are composed of two 

 elements. For the purposes of this lecture, it is 

 not deemed necessary to enter into these or many 

 other details of this complicated subject. For 

 comprehensive and admirable critical reviews of 

 recent theories of immunity and Ehrlich's hy- 

 pothesis of the receptors, I would refer to Dr. 

 Ritchie's papers in the Journal of Hygiene, 

 Vol. II., No. 2, and succeeding numbers; and to 

 Dr. Aschoff's paper in Zeitschrift f. allgem. Physi- 

 ologie, Bd. III., Heft 3. 



