SECTION II 

 DIAGNOSIS OF CERTAIN DISEASES 



DIPHTHERIA 



Diphtheria is a local disease with general symptoms. The local 

 symptoms are due to the local action of the bacillus which causes 

 the disease, while the general symptoms are due to the toxin or 

 poison which they produce, and which is carried in the blood- 

 stream to the brain, heart, and other organs. Now the local 

 symptoms are comparatively unimportant, and it is to the general 

 symptoms caused by the toxin that diphtheria owes the greater 

 part of its high mortality. Diphtheria antitoxin neutralizes this 

 toxin (much in the same way as an alkali neutralizes an acid), 

 and prevents it from harming the vital structures ; but it does not 

 repair the harm that the toxin has done. It is obvious, therefore, 

 that we must not make our diagnosis of diphtheria from the 

 general symptoms if the antitoxin treatment is to do any good. 

 The diagnosis is to be made from the local symptoms, and this is 

 what we can rarely do by ordinary clinical methods at a stage 

 sufficiently early to get the full value of the antitoxin treatment. 



The practitioner has a choice of two methods. He may inject 

 all patients who suffer from sore throats which present the slightest 

 resemblance to those seen in diphtheria, or he may employ 

 bacteriological methods of diagnosis. The former method may be 

 applicable in an epidemic of diphtheria, but suspicious throats are 

 common and antitoxin expensive. In most cases it is necessary 

 to have recourse to the second method. 



Most sanitary authorities have now recognized that it is their 

 duty and privilege to provide for the bacterial investigation of 

 supposed diphtheria free of charge to doctor and patient, and 

 supply outfits to be used for taking the material and transmitting 

 it -to the laboratory. When the practitioner lives within easy 



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