IMMUNITY 85 



INHERITED IMMUNITY 



Natural immunity is, of course, transmitted from 

 parent to offspring, but acquired immunity is transmitted 

 but slightly, if at all. A certain degree of immunity is 

 transmitted by the female immunized animal to her off- 

 spring in certain instances, as in the case of sheep im- 

 munized to anthrax, but this does not obtain in case of 

 the male parent. 



A certain degree of passive immunity occurs in the 

 newborn whose mother has had recent injections of 

 antitoxin. Antitoxin may also be transmitted from 

 mother to offspring through the milk. The immunity 

 thus conferred is not sufficient to be depended upon, and 

 further immunizing procedures should always be insti- 

 tuted. Agglutinins are occasionally transmitted to the 

 offspring. Opsonins are not transmitted to the offspring 

 in the uterus, but are present in the milk of nursing 

 animals, and they are probably absorbed by the nurs- 

 ling via the digestive tract. 



METHODS OF PRODUCING ACTIVE ACQUIRED IMMUNITY 

 Inoculation with Living Virulent Bacteria. This form 

 of inducing immunity is impractical and little used. 

 It has been resorted to experimentally with more or 

 less success in animals of diminished susceptibility. 

 Small non-fatal doses are administered and gradually 

 increased. The only instance of the use of this method 

 in man is in Ferran's inoculation against cholera. 



