120 THE ACUTE SELF-LIMITED INFECTIONS 



by the direct application of the bacilli to the abraded mucous 

 membrane of the nose. For the treatment of acute influenzal 

 colds there is no practicable specific therapy by the use of 

 antisera or bacterins. When, however, there is a prolonged 

 catarrh of sinuses, larynx, or bronchi, or when it can be 

 shown that a person is harboring the bacilli, it is perfectly 

 feasible to employ dead organisms as a bacterin, using, 

 wherever possible, a culture from the patient. This is prac- 

 tically never in pure cultures and mixed vaccination is the 

 rule. For pneumonia, pleurisy, and so forth we know nothing 

 of the practical nature of antiserum, but for meningitis it has 

 been found to have some curative effect. It is introduced 

 into the spinal canal after withdrawal of some fluid to make 

 room for it. It is made by injecting horses with increasing 

 numbers of the bacilli and separating the serum as for 

 diphtheria antitoxin. 



BACILLUS PESTIS. 



Bubonic plague, or "the plague" or "pest," is an acute 

 infectious disease caused by the Bacillus pestis, and char- 

 acterized by high fever, suppuration, swelling of the lymph 

 glands, and a severe grade of bacteremia. In the so-called 

 pneumonic form, a pulmonary inflammation dominates the 

 clinical picture, but the infective nature of the disease is the 

 same. Occasionally in very severe attacks, subcutaneous 

 hemorrhages occur; this is called "black death." The 

 commoner or lymph gland form occurs when the bacteria 

 gain entrance by flea bites, skin cracks or wounds, while the 

 pneumonic type follows inhalation of the germs. 



The bacteria enter chiefly through the skin by way of 

 minute wounds, or, as was shown in India, by the bite of a 

 rat flea. Rats and mice, indeed all rodents, are susceptible to 

 plague, it practically being endemic among them in certain 

 countries, and they contract it from biting the living, feeding 



