SMALLPOX, SYPHILIS, CANCER, ETC. 209 



parasites. By appropriate treatment when they are culti- 

 vable on artificial media such vaccines can be ' fixed ' at any 

 given grade of virulence. Although it is not cultivable 

 artificially the virus of hydrophobia can be fixed as explained 

 above. 



In misleading language the term c vaccine ' has been 

 applied to an important class of preparations of dead 

 leria. They should be called ' pro- vaccines.' In the 

 J x^af jtha typhoid group of 



d its originators 



>uld be found to 



ice to humanity 



. Unfortunately 



* serum or pro- 



ice the course of 



A community un- 



vaccinated ana iievoj. ^~ r js or scarlet fever 



suffers terribly whenever smallpox or other exanthematous 

 fever appears in it : the healthiest, noblest specimens of 

 manhood and womanhood die, we having no remedy. 



Ought we to seek attenuating hosts for the parasites of 

 measles, scarlet fever, &c. as we have the calf to attenuate 

 the virus of smallpox ? Our knowledge of syphilis gives us 

 pause. We know that immunity to syphilis means having 

 the disease : having the specific parasites living in the 



tissues of the immune person. 



14 



