152 CLINICAL BACTERIOLOGY AND 



virulent dose of infection than the others, considering their 

 surroundings are identical and the infection apparently the 

 same ? Clearly, then, there must be in this animal some 

 defective condition which was non-existent in the others. 



As we have already seen, purpura makes itself manifest 

 at the tail end of debilitating specific diseases. We know 

 a regular war has been going on between the bactericidal 

 forces of the body on the one hand, and the bacteria on 

 the other. 



The serum of the blood, as we have seen, provides these 

 forces, and usually after a bacterial attack the bacterio- 

 tropic indices rise and the patient becomes more resistant ; 

 but this degree of specificity is only potent to the bacteria 

 present, and while these immune bodies are being elaborated 

 for the purpose' of protecting the system against the active 

 pathogenic bacteria, a latent bacterium makes its presence 

 felt by taking on a pathogenic role, the antibodies are not 

 sufficiently prepared to resist this fresh invader, the 

 blood- serum undergoes a retrogressive change, the endo- 

 thelial cells also become affected in some way, and the 

 characteristic petechial lesions and the serous effusions 

 soon follow. This, of course, is only hypothesis, but we 

 venture to think we must look to some alteration of the 

 serum for the production of the purpuric lesions. The 

 point is, what is the nature of the alteration and how is it 

 brought about ? 



For vaccine- therapy to be of any service in purpura, we 

 must be somewhat empirical in our methods, and we will 

 continue to be so until we know more of the pathology of 

 this disease. In the meantime it becomes us to utilize what 

 knowledge we possess to protect our patient from the 

 destructive influences of this fatal disease. 



Autogenous vaccines should therefore be made from the 

 bacteria which have caused the original condition, and they 

 should be combined with serums if considered advisable. 



The intratracheal injections of Lugal's solution must also 

 be strongly recommended as an adjuvant. 



