244 IMMUNOLOGY 



is given. Autopsy shows hyperemia of the kidneys and adrenal 

 glands, numerous small petechial hemorrhages scattered through- 

 out the bod}^ and an increased amount of tluid in the serous 

 cavities. The latter represents a serous exudate. 



Effect on Dogs, Sheep, and Birds.— Roux and Yersin (cited by 

 Loeffler, 1913) studied the effect of toxin in sheep, dogs and birds 

 as well as guinea pigs and rabbits. All were found susceptible 

 to its action. They noted that in many cases where the dogs did 

 not die they developed paralysis. Filtrates of 7- to 10-day-old 

 broth cultures produced the same clinical and pathological picture 

 as that produced by the injection of virulent organisms. Dean 

 (1913) refers to an interesting observation of Martin (1898) that 

 an organism may be toxicogenic and yet nonvirulent. This ob- 

 servation indicates that to produce diphtheria the organisms must 

 establish themselves and by the injury of tissues create conditions 

 favorable to the absorption and distribution of toxin. 



Diphtheria in Man. — Diphtheria is usually classified as one of 

 the diseases of childhood. Nursing infants rarely contract diph- 

 theria either through lack of exposure or as a result of passive 

 immunity obtained from the mother. Many adults are susceptible. 



The incubation period is usually twenty-four to forty-eight 

 hours. While the primary focus of infection may be in a wound 

 or on the mucous membrane of the eye or vagina, it is usually in 

 the nose, throat or trachea. The local inflammatory response to 

 infection is characterized by redness, edema and the outpouring 

 of an inflammatory exudate rich in fibrin which forms a character- 

 istic membrane. This latter, according to Mallory* (1913), "may 

 appear white, dirty white, brownish, grayish or almost black in 

 color." It is made up of fibrin, bacteria, leucocytes, desquamated 

 epithelial cells and cellular debris. The breath of the patient has a 

 peculiar odor which is almost of diagnostic importance. In laryn- 

 geal diphtheria the patient is not only injured by the toxin but the 

 membrane found in the trachea may mechanically obstruct breath- 

 ing and lead to suffiocation. There is great variation in the 

 amount of membrane formation in diphtheria. In some cases it 

 may not be observed while in others it is quite extensive and readily 

 noticed. 



♦Mallory in The Bacteriology of Diphtheria by Nuttall and Graham-Smith, 

 Cambridge Univer.sity Press. 



