680 ACTIVE IMMUNIZATION 



observing ordinary care, and at least ordinary cleanliness, in the treat- 

 ment of the vaccinal wound. 



It is exceedingly difficult to determine the source of infection in each 

 case of vaccinal tetanus, but experimental investigations would tend 

 to indicate that the virus itself is seldom, if ever, the vehicle of infection. 

 John F. Anderson, Director of the Hygienic Laboratory, in testimony 

 given before the Pennsylvania State Vaccination Commission, stated 

 that in experiments carried out on monkeys and guinea-pigs with vaccine 

 lymph purposely contaminated in the laboratory with countless numbers 

 of tetanus spores, it was found impossible to communicate tetanus 

 in this manner, although the vaccinations were more severe than the 

 ordinary vaccinations performed on man, in that several places were 

 inoculated and the areas abraded were large. Anderson stated that 

 his " conclusion from these experiments is that it is almost impossible 

 to produce tetanus, even with vaccine virus that contains tetanus 

 germs in it, by the simple act of vaccination." 



Since 1909 there were approximately 100,000 specimens of vaccine 

 virus examined in the Hygienic Laboratory, particularly with the pur- 

 pose of determining the presence of tetanus germs or their products. 

 The vaccine was purchased in the open market, and the examinations 

 were made as thoroughly as it was possible to make them. To use 

 Anderson's words: " We have never succeeded in finding any evidence 

 of the presence of the tetanus organism or its products in vaccine virus." 

 (Report of the Commission.) 



It would appear, therefore, that virus prepared according to modern 

 methods and with all recognized precautions is safe. In view of the 

 incidence of tetanus following other injuries, it is reasonable to conclude 

 that most cases of vaccinal tetanus are secondary wound infections, 

 and therefore largely preventable. 



2. Syphilis. With the use, years ago, of humanized virus, and par- 

 ticularly in the days of arm-to-arm vaccination, extremely rare instances 

 of the transmission of syphilis have been known to occur. Since, how- 

 ever, the use of calf virus, which is the virus exclusively employed in this 

 country, such an accident is absolutely impossible, as calves are not 

 susceptible to luetic disease. 



3. Cancer, foot and mouth disease, tuberculosis, and various chronic 

 skin eruptions have been attributed to vaccination by its opponents; 

 none of these claims has, however, been substantiated. 



Protective Value of Vaccination. Of the value of the protection 

 afforded by vaccination against smallpox there can be no doubt in the 



