VACCINE-THERAPY 169 



may give no reaction. Might this fact not be partly due to 

 the probable condition that all tubercle bacilli have been 

 killed off, not only by their own toxins, but by the toxins 

 and other poisons from the secondary invasion ; and that the 

 animal at this stage is not only not suffering from a tuber- 

 culosis in the strictest sense, but from an acute specific 

 disease due to the secondary bacterial invasion ? 



On looking through the whole symptomatology of tuber- 

 culosis, one must confess there does not exist a single diag- 

 nostic manifestation which may be taken as proof positive of 

 the presence of this disease. There are, however, several 

 symptoms invariably present, which, if weighed up singly 

 and interpreted collectively (particularly if a process of 

 what might be called symptomatic elimination is adopted 

 also), will give to the trained practitioner strong proof upon 

 which to base his conclusions. 



The clinician who relies upon a given set of orthodox 

 symptoms, but fails to interpret minor details even if they 

 be unorthodox, is more likely to make errors of diagnosis 

 than the practitioner who embarks upon his clinical 

 inquiry with a more open mind. 



For purposes of diagnosis and descriptive convenience, 

 we propose to divide tuberculosis according to the systems 

 and organs it affects, not forgetting in practice, however, 

 that more than one and even all the systems may be 

 affected at the same time and in the same animal : 



1. Tuberculosis of the respiratory system. 



2. Tuberculosis of the alimentary system. 



3. Tuberculosis of the genital system. 



4. Tuberculosis of the nervous system. 



5. Tuberculosis of the lymphatic system. 



6. Tuberculosis of the mammary system. 



Tuberculosis of the Respiratory System. 



When a primary invasion of tubercle bacilli takes place, 

 probably through inhalation, an irritation of the bronchial 



