514 IMMUNITY AND PROTECTIVE INOCULATION 
of the disease by vaccination was not attained until rigid methods of 
isolation and disinfection were carried out. Just what these methods 
are to be in each particular case will be indicated by a definite knowl- 
edge of the cause and the nature of the disease in question. 
The methods for immunization that give the greatest promise in 
aiding in the solution of the problem of the control of infectious diseases 
are those productive of a passive immunity. Although these are 
temporary in duration they are effective immediately and conse- 
quently tend to save individuals when they are applied in the period 
of incubation or before a possible exposure. They protect the animal 
until the virus can be eliminated and its environment made safe. 
The advantages of introducing preventive measures are: 
The tendency to eliminate the virus of the disease if it is present, 
and to keep it away if it has not already appeared. 
The animals are free from the virus and there is no danger of their 
subsequently developing lesions due to the localization of the attenu- 
ated microorganisms. 
The separating of the well animals from the sick ones and from the 
infected stables, pens, yards, or fields is not usually an expensive 
procedure. The stables and yards can be disinfected and the infected 
fields can be utilized for other purposes until the virus has been de- 
stroyed by its own limitations of endurance. In this connection, it is 
well to call attention to the successful efforts that are being put forth 
to eliminate the cattle tick from the Southern States and thus prevent 
Texas fever. 
REFERENCES 
Crrron. Immunity. Philadelphia, 1912. 
Enruicu. Studies on immunity. New York, 1906. 
Ernst. Modern theories of bacterial immunity. Boston, 1903. 
Jowett. Notes on blood-serum therapy. London, 1907. 
Kotmer. Infection, Immunity and Specific Therapy. 1915. 
Kraus uno Levanitt. Handbuch der Technik und Methodik der Immuni-— 
sforschung. 1909. : 
Mercunikorr. Immunity in infective diseases. Cambridge, 1905. 
Mucu. Die Immunitatswissenschaft. Wurzburg, 1911. 
MU.zer. Vorlesungen tiber Infektion und Immunitat. Jena, 1910. 
10. Nurratyt. Blood immunity and blood relationship. Cambridge, 1904. 
11. Sopernuem. Deutsche Med. Wochenschrift, 1904, S. 27. 
12. SrerNBeRG. Immunity, protective inoculations in infectious diseases and 
serum-therapy. New York, 1895. 
13. STERNBERG. Infection and immunity. New York, 1903. 
14. Vaucuan. Protein split products in relation to immunity and disease. 1913. 
of 
SPN Ton > © wo 
