278 THE PRINCIPLES OF IMMUNOLOGY 



fifteen minutes. Ultra-violet rays have been used. Chlorine has also 

 been employed, but the resulting hydrochloric acid is difficult to remove. 

 Whitmore and Fennel used powdered potassium iodid. This was added 

 to olive oil and sweet almond oil; iodin was liberated in sufficient 

 amount to sterilize the oil, and was taken up in the oil molecule so that 

 no free iodin could be detected. Sweet almond oil is sterilized in about 

 three days, but it requires about ten days to sterilize olive oil. It is not 

 known, however, how the suspension in oil affects the antigenic power 

 of the vaccine, but certain workers claim to get better results than by 

 the use of saline vaccines. Against the use of lipovaccines is the 

 possibility of fat embolism from accidental entrance of the vaccine 

 into a vein, but Graham considers this factor of minor importance since 

 the amount of oil is small. He injected as much as 0.8 c.c. of oil into 

 the ear vein of a rabbit and observed only a slight passing dyspnea 

 and no other evidence of discomfort. Care should be taken, however, 

 to administer the vaccine subcutaneously and to avoid veins. Drawing 

 out the plunger of the syringe after the needle has been introduced 

 determines whether or not an important vein has been entered. The 

 upper arm beneath the insertion of deltoid muscle is usually selected 

 for the injection. The region of the scapular or pectoral muscles 

 may do as well. 



Contraindications. In prophylactic immunization it is of im- 

 portance to ascertain whether the patient has latent or active 

 infection. In active tuberculosis vaccination is considered danger- 

 ous. Caution should be observed in diabetes, parenchymatous nephritis 

 and carcinoma. 



VACCINATION WITH LIVING VIRUS 



Smallpox Vaccination. Although inoculation with the virus in 

 smallpox in an attempt to produce a mild attack of the disease had 

 been practiced for centuries and although for many years it had been 

 observed that an attack of cowpox rendered man immune to smallpox, 

 it remained for Jenner in 1796 to furnish the scientific proof of the 

 efficacy of vaccination with cowpox in the prevention of smallpox. 

 Jenner's publications were so convincing that the method soon attained 

 widespread use and was introduced into America in 1800 by Dr. Benja- 

 min Waterhouse, of Boston. The work of the latter investigator was 

 especially well conducted and convincing. In 1894 Copeman demon- 

 strated the protection of monkeys against smallpox by vaccination with 

 cowpox, and this was subsequently confirmed by Brinckerhoff and 

 Tyzzer. The introduction of vaccination following Jenner's publication 

 immediately led to marked reduction in the incidence of this disease 

 and its mortality. The table on page 279 (taken from O'Connell, " Vac- 

 cination; What It Is, etc.," circular New York State Department of 

 Health, 1908) gives a clear indication of the reduction of mortality. 



Up until fairly recent times vaccination was practiced by inocu- 

 lating patients with the fragments of the crust obtained from others 

 who had been successfully vaccinated. This method has been aban- 



