308 Microbes and You 



TEMPERATURE 



Some rather interesting studies have been conducted by C.-E. 

 A. Winslow and his co-workers on the relationship of temperature 

 to disease. They found that a temperature of between 84° F. and 

 89° F. resulted in a marked decrease in at least one antibody, 

 HEMOLYSIN, about which more will be written later. Such studies 

 indicate a possible explanation of some differences recorded in the 

 resistance of individuals in temperate climates as compared with 

 persons in tropical or in sub-tropical areas. The presence of spe- 

 cific disease vectors must also be considered before hasty conclu- 

 sions are drawn relative to a single factor like temperature. 



It is known that certain diseases have a seasonal incidence 

 which may bear a direct or an indirect relationship to temperature. 

 The higher rate of upper respiratory infections during the colder 

 months of the year, for example, may be related to greater indoor 

 living in heated homes with an atmosphere low in humidity. The 

 drying action of such air on mucous membranes may be more 

 important than the effect of outside temperature on the respiratory 

 tract. 



IMMUNITY 



The term immunity is derived from the Latin word immunis, 

 which means exempt. The word todav has various meanings de- 

 pending upon the specific use to which it is put. From our point 

 of view immunity might be considered to be the tendency to resist 

 infectious disease. This definition implies that there are degrees of 

 resistance, and this happens to be the case. Immunity to some 

 virus-induced diseases, for example, may be virtually absolute for 

 varying periods of time; or there may be decreasing degrees of 

 immunity with other viruses and other microbes, until the degree 

 of resistance induced is so weak as to be ineffectual. 



THEORIES OF IMMUNITY 

 It was only natural for keen observers eventually to notice that 

 individuals who contracted certain diseases rarelv became ill with 

 that same disease a second time. Still other diseases, however, 



