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 ' vaccine ' has been 

 applied to an important class of preparations of dead 

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

 late war the immunising pro- vaccine of the typhoid group of 

 bacteria appears to have been successful and its originators 

 deserve our gratitude. If a pro-vaccine could be found to 

 replace the vaccine efficiently, such a service to humanity 

 would be greater even than that of Jenner. Unfortunately 

 no sterile substance, whether immunising serum or pro- 

 vaccine, has as yet been found to influence the course of 

 any of the common exanthemata. 



Specific remedies for specific fevers ? A community un- 

 vaccinated and never exposed to measles 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 



