46 OFFENSIVE FORCES OF INVADING MICROORGANISM 



immune animal, the question naturally suggests itself, whether, after 

 all, we are not dealing with a type of immunity which is different 

 from the other forms that are commonly recognized. This question 

 will be discussed at greater length in a later chapter; suffice it to say 

 at this place that there is evidence to show that this type of immunity 

 is essentially an antitoxic immunity, but one in which the antitoxic 

 effect is probably the outcome of structural changes in the chemical 

 make-up of the cell and not the result of a liberation of antitoxic 

 groups from the cell and their action upon toxin molecules in the 

 circulation. 



Summary. To sum up: So far as our knowledge of the actual 

 aggressive forces of the invading bacteria are concerned w r e must 

 admit that, barring the morphological changes with which we have 

 become acquainted, and which we have come to look upon as pas- 

 sively aggressive forces, active forces furnished by the living organ- 

 isms during the infection, have not been satisfactorily demonstrated. 

 But we have seen that bacterial decomposition products in them- 

 selves possess a certain infection-favoring influence and are in this 

 sense aggressive. That a decrease in the offensive forces of the host, 

 finally, is in a measure equivalent to an increased aggressivity of the 

 infecting bacteria is practically self-evident. These forces will be 

 studied in subsequent chapters, but before entering upon their con- 

 sideration it may not be out of place to briefly review our knowledge 

 of those products of bacterial activity or degeneration which play a 

 role in the production of the picture of the so-called infectious diseases 

 and their probable manner of action. 



BIBLIOGRAPHY. 



Bail, O. Versuch eines natiirlichen Systems d. bakteriellen Infektionen. 

 Jahresb. u. d. Ergeb. d. Immunitatsforsch., 1911, vii, 91. 



Gal, F. Untersuchungen u. d. Virulenzproblem, Zeit. f. Imm., 1912, xiv, 685. 

 Strouse, S. Experimental Studies on Pneumococus Infections, Jour. Exp. 

 Med., 1909, xi, 743. 



Bail, O. Analyse d. Virulenzbegriffes, Fol. serol., 1908, i, 402. 

 On the Agressin Question: 



Kruse. Ziegler's Beitrage, xii. 



Deutsch. L., u. Feismantel. Die Impfstoffe und Sera. Leipzig, Thieme, 1903. 



Bail, O. Arch. f. Hygiene, lii, 272, u. liii; Berlin, klin.-therap. Woch., 1905, 



No. 37. 



Wassermann u. Citron. Deutsch. med. Woch., 1905, xviii, 573. 

 Citron. Centbl. f. Bakt., 1905, xl, Heft. 1, 153. 



Ottolenghi, D. Ueber d. Kapsel d. Milzbrandbazillus, Zeit. f. Imm., 1911, lx, 

 769; ibid., 1912, xii, 386. 



Zinsser, H., u. Dwyer, J. G. Proteotoxins (anaphylatoxins) u. Virulence, 

 Jour. Exp. Med., 1914, xix, 582. 



