DIPHTHERIA. 43 



PART 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 

 neutralises this toxin (much in the same way as an 

 alkali neutralises 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, therelore, 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 ordin- 

 ary 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 



