November 21, 1902.] 



SCIENCE. 



813 



teria, represented by the bacilli of tetanus, 

 of diphtheria, and of botulism, character- 

 ized by the secretion of powerful soluble 

 toxins, and the much larger group, contain- 

 ing most of the other pathogenic bacteria, 

 which do not secrete similar strong toxins, 

 for it is only the former which give rise to 

 the production of antitoxic serum of 

 marked protective and curative power. 



The form of immunity resulting from 

 injections or natural infections with the 

 second class of bacteria belongs mainly to 

 the bacteriolytic type, in which the com- 

 plete antibody is not a single substance, 

 like antitoxin, but is composed of two 

 distinct elements, intermediary body and 

 complement, of which only the former is 

 produced or increased in the process of im- 

 munization. The bacteriolytic serums are 

 also under suitable, but not readily con- 

 trolled conditions, protective and curative, 

 but owing, it would seem, mainly to the 

 duplex nature of the antibody their suc- 

 cessful therapeutic application meets dif- 

 ficulties which have not yet been over- 

 come. The great practical problem of 

 bacteriology to-day is to make available 

 to medical practice the bacteriolytic ser.- 

 luns such as antityphoid, antipneumococ- 

 cus, antistreptococcus, antiplague, anti- 

 dysentery serums. Such work as that of 

 Marmorek, of Wassermann, of Neisser and 

 Wechsberg, of Ainley "Walker, vipon the 

 production, the properties, the conditions 

 underlying the action of these serums is, 

 therefore, highly important. 



Our knowledge of the constitution and 

 action of the intracellular bacterial poisons 

 is most incomplete and at present cannot 

 be applied in any very definite and satis- 

 factory way to the explanation of the mor- 

 bid phenomena of infectious diseases. Such 

 investigations as those undertaken by Mac- 

 fadyen and Rowland at the Jenner Insti- 

 tute of Preventive Medicine upon the ex- 

 pressed juices of bacterial cells promise to 



shed light upon this subject and in gen- 

 eral upon the vital processes of bacteria. 

 Of great value also are the recent re- 

 searches of Vaughan upon intracellular 

 bacterial poisons! 



I find it difScult to reconcile myself to 

 the doctrine that bacteria, such as the 

 typhoid bacillus, the pneumococcus, and 

 others of the class now under consideration, 

 do their chief injury to the body, not while 

 they are lively and vigorous, but after they 

 become corpses and in consequence set free 

 their protoplasmic poisons. Still this 

 latter conception is the basis of a coherent 

 hypothesis of infection, elaborated most 

 fully recently by Radziewsky,* which rests 

 upon a considerable amount of accurate 

 observation and interesting experimental 

 work. There can be no doubt that in the 

 course of many infections there goes on an 

 enormous destruction of the bacteria con- 

 cerned so that the numbers of those indi- 

 cated at any given time by microscopical 

 examination and by cultures may repre- 

 sent only an insignificant fraction of the 

 total progeny of the first invaders. I have 

 been much interested in this phenomenon, 

 since I became familiar with it over twelve 

 years agof in pneumococcus infections 

 through the employment of a method which 

 revealed in the exudates degenerating and 

 dead pneumococci and their empty capsules 

 in numbers often far exceeding the intact 

 organisms ; indeed, in some cases so many 

 that they formed a large part of the ex- 

 udate. 



While all due weight should be given to 

 such facts as these, the objections to the 

 acceptance of the hypothesis just mentioned 



* Radziewsky, Zeitschfift fur Hygiene, 1900, 

 jSfXIV., p. 185, and 1901, XXXVII., p. 1. 



t Welch, Bulletin of the Johns Hopkins Hos- 

 pital, July, 1890, and December, 1892. Michaelis, 

 Berl. klin. Woch., 1902, No. 20, has recently re- 

 ported the same findings. 



