322 BOARD OF AGRICULTURE. [Jr.n. 



From the earliest days of the medical profession the sad 

 fact has been recognized that, when consmnption resulting 

 from this tubercular deposit has become fully established in 

 the substance of the lungs, or lung tissue has been destroyed, 

 recovery seldom takes place. Many and in fact most of 

 them died, said Hippocrates ; and all of us who have prac- 

 ticed medicine are compelled in truth to say the same thing. 

 For twenty-four hundred years, and probably through all the 

 ages, the best medical minds the world has ever produced 

 have coped with this disease ; and yet, with all their studies 

 and the accumulated wisdom of them all, about one-seventh 

 of all the deaths that occur in the human family yearly are 

 to be attributed to it. There is not a clime nor a period of 

 life in which it may not be found ; the rich and the poor, 

 the civilized and the uncivilized, become its prey ; and, since 

 it cannot be cured, can we reduce the number of its victims, 

 and how can it be done? 



Tuberculosis is the specific infectious disease produced by 

 tubercles, which are in turn special products of a distinct 

 micro-organism known as the Bacillus tuberculosis ; evidence 

 incontrovertible shows that they are products of this distinct 

 bacteria. Though the word tubercle is as old as anatomy, 

 the term tuberculosis, in designation of a definite disease, is 

 modern, comparatively. 



The history of tuberculosis falls naturally into five periods : 

 The first, that of ancient history. The second, beginning with 

 the birth of anatomy in the sixteenth century, furnishing 

 the first definite knowledge regarding changes or lesions of 

 structure. The third was in the first quarter of the nine- 

 teenth century, following the discoveries of Laennec and 

 Bailey, made memorable by the discovery of auscultation as 

 a means of diagnosis. It was the ""enius of Laennec in this 

 discovery which first rendered possible a diagnosis of this 

 disease in life. The fourth was introduced late in the last 

 half of the nineteenth century, with the inoculating experi- 

 ments of Villemin in 18G5. The fifth period was announced 

 with the brilliant revelations of Koch in 1882, reijardins; the 

 cause of tubercle and the etiology of disease. It is to the 

 two latter periods that your attention is more particularly 

 called. 



