TOXINS AND ANTITOXINS 245 



Symptoms. — Clinically, tJic patient exhibits only a moderate 

 fever, a rapid pulse and more or less prostration. His first com- 

 plaint may be onl}^ that of a sore throat. If a blood count is made, 

 it usually reveals a moderate leucocytosis. In malignant cases 

 there may be extensive enlargement of the regional lymph glands, 

 extreme discomfort and prostration. 



Pathology in Man. — Mallory (1913) gives an excellent discus- 

 sion of the pathology of diphtheria. He says that the local lesions 

 are essentially the same in that they show "degenerative changes 

 in the epithelial cells and underlying tissues combined with an 

 extensive fibrinous exudate from the blood vessels." Broncho- 

 pneumonia, myocarditis and paralysis of the soft palate are not 

 uncommon complications of untreated diphtheria. For further 

 information the student is referred to Mallory 's excellent dis- 

 cussion of autopsy findings on a fairly large series of fatal cases 

 of diphtheria. 



Causes of Death in Diphtheria.— Meyer and Gottlieb (1914) 

 consider that diphtheria toxin is a specific vascular poison. The 

 toxin also acts centrally upon the nervous system. Thus the 

 direct injury of heart muscle, vascular system and adrenal glands 

 combined with the effect upon the nervous system (vagus, phrenic, 

 etc.) is thought to explain the profound drop in blood pressure 

 and cardiac death seen in fatal cases. 



Source and Nature of Diphtheria Toxin. — The true bacterial 

 "exotoxins" are generally described as secretory products of 

 the bacterial cell. According to this conception they resemble in 

 some respects the extracellular enzymes that are formed and 

 liberated bj^ the cell. Dernby (1926) regards diphtheria toxin as a 

 higher degradation product of proteolysis. Wells (1929) sug- 

 gests that bacterial toxins may be toxic radicals attached to pro- 

 teins. According to Eaton (1938) the theory that diphtheria 

 toxin is formed by enzymatic degradation of proteins in the cul- 

 ture media is becoming less tenable in the light of present re- 

 search. He also says that there is no experimental evidence to sup- 

 port the theory that toxins are conjugated proteins containing a 

 physiologically active prosthetic group. Different strains of C. 

 diphtheriae produce qualitatively the same toxin although there 

 are definite quantitative differences even under optimum condi- 

 tions. 



