Papeks ox Medicixe, Public Health axd Saxitatiox 79 



Such a reaction occurs only in the indi\ddual who has 

 no acquired immunity form previous tuberculous infec- 

 tion. These lesions, it appears from numerous authori- 

 ties, occur in the infant under two years of age, and give 

 rise, according to Hesse and others^ " to more deaths dur- 

 ing the first year of life than any other period except 

 between 35 and iO. This primary lesion occurs in one 

 class of adults only, those who have been out of touch, 

 from infancy, with civilization, ^vith these it is parti- 

 cularly severe and often fatal." 



Eomer, who reports on tuberculosis in Argentina and 

 elsewhere, concludes that, "the less extensive the preva- 

 lence of tuberculosis in a population the greater the fa- 

 tality of tuberculosis, or reversing the process, the more 

 widespread tuberculosis is in a population, the less fatal 

 is the form of the disease." In civilized communities 

 the primary lesion does not occur in adults. The primary 

 lesion is less fatal to infants, and the secondary lesion 

 less fatal to adults. 



It is the slowness of development of the secondary 

 lesion and the reaction of the tissues to the toxins of the 

 tubercle bacillus that convince one of the existence of a 

 potential immimity. Statistics generally agree that the 

 tuberculous lesion is found in more than 95 per cent of 

 autopsies from deaths not tuberculous. These lesions 

 show a calcareous center surrounded by a firm fibrous 

 wall of tissue, and a third line of defense consisting of 

 giant cells and endothelial leucocytes. It is this evidence 

 that makes one certain that innnunity can be developed. 



On the other hand the renmants of defensive structures 

 which are seen in the autopsies of those dead of tuber- 

 culosis give us additional evidence of this immunity. 

 Here we tuid these walls of fibrous tissue, not of micros- 

 copical size, but in masses firm and solid, oftentimes 

 thicker than one 's hand,^- 



^" The Significance of Tuberculosis in Infants and Children, Alfred F. 

 Hess, J. A. M. A. January 11, 1919. 



^ Review of Fulminating Tuberculosis of Tracheobronchial Glands, A. 

 Dumas, J. A. M. A., June 7, 1919. 



^ Manifest Pulmonary Tuberculosis, Col. G. E. Bushnell, The Military 

 Surgeon, April, 1918. 



