IMMUNITY IN TUBERCULOSIS 247 



I do not intend to discuss the value to the clinician of this interest- 

 ing method and Wright's observations based upon it. The subject ap- 

 pears to me to be one of great intricacy and therefore to be approached 

 in a spirit of proper criticism despite its evident allurements. My pur- 

 pose in mentioning it at all is to bring again to your attention a method 

 of exciting the tuberculous body to put forth an effort at self immuniza- 

 tion which is sometimes efficient to a marked degree. It is not the 

 injected tuberculin that accomplishes directly the changes in the condi- 

 tion of the patient, for there already exists, doubtless, an excess of 

 similar poisons in the tuberculous foci in the body. The healthy body, 

 indeed, does not react in this manner and is not to be protected, endur- 

 ingly, from tuberculous infection by a previous treatment with tuber- 

 culin. As Koch's phenomenon shows the tuberculous organism to have 

 developed defenses against subsequent tuberculous infection which the 

 normal body does not possess in equal degree, the employment of tuber- 

 culin indicates that the diseased body can be aroused artificially to put 

 forth a stronger effort than its unaided natural forces enable it to make, 

 in order that the disease may be overcome. Herein resides a great 

 principle, an immense power for good, and, consequently, a great hope 

 for future progress in the rational and specific treatment of tubercu- 

 losis in man. Efficient efforts at suppression of the causes of tubercu- 

 losis, deeper knowledge of the principles of bacterial immunity, are 

 the two forces which in time may stay the ravages of the 'White 

 Death.' 



