520 INFECTION AND RESISTANCE 



and apparently complete, the resistance becomes a general one. In 

 animals like the rabbit in which the lesion or in other words 

 pathological response, occurs in a few organs only, the resistance is 

 limited to the particular organ or organs that have previously de- 

 veloped a lesion. 



It must not be forgotten that such a resistance probably persists 

 for a limited time only, and does not imply the sterilization of the 

 body and the complete destruction of the microorganisms. These 

 may, and probably do, remain alive and potent in various parts of the 

 body, capable of again setting up new lesions in parts hitherto unin- 

 volved or again susceptible after a diminution of their local, acquired 

 resistance. That the virulent treponemata may remain thus latent, 

 alive and virulent has been sufficiently shown in animal experimen- 

 tation by successful inoculation with tertiary lesions and by the 

 frequent late accidents, especially of the nervous system, in indi- 

 viduals apparently cured or for a long time without symptoms. 



It would seem when we analyze the conditions in syphilis, that 

 complete sterilizing immunity or, in other words, complete cure, 

 occurs but rarely without specific medicinal aid, and that the un- 

 treated syphilitic (if such an unfortunate individual exists in a 

 civilized country) might go on to apparent cure, in that a general 

 syphilization of his body would bring about a general resistance, 

 but would always harbor virulent treponemata which could cause 

 recrudescences in parts in which resistance was diminished, and 

 eventually kill by degenerative processes in the central nervous sys- 

 tem where many injuries cannot be compensated for as is possible in 

 other organs. 



The resistance which develops is apparently a new attribute only 

 of the cell groups which have undergone direct reaction with the 

 treponemata. This resistance may consist merely in the complete 

 failure of the tissue cells to react to the virus, a sort of "tissue indif- 

 ference" or "Anergie." It may be, however, and probably is, ac- 

 companied by a certain amount of active defense in the form of local 

 phagocytosis of the treponemata by the fixed tissue cells. 



THE INFLUENCE OF INJECTIONS OF NON-SPECIFIC SUB- 

 STANCES UPON INFECTIOUS DISEASES 



Therapy of infectious diseases has been very logically dominated 

 in the past by attempts to increase resistance, either passively, by 

 the injection of specific anti-sera, or actively, by treatment with bac- 

 terial antigens or their derivatives. The idea of specificity, in other 

 words, has dominated such attempts almost exclusively. In spite of 

 this, however, there has gradually grown in the minds of bacteriolo- 

 gists an impression that not all the effects of the injection of bacterial 



