Stfirk, in 178f», gave a very complete description of the miliary 

 tubercles, and Reid, in the same year, advanced the idea that the}' 

 were not enlarged lymphatic glands, but independent formations in 

 the substance of tiie lungs. He denied that there were any lymphatic 

 glands in the substance (parenchyma) of the lungs ; but his contem- 

 poraries did not agree with him, but h6ld to the opinion that the tu- 

 bercles in the lungs were glands, viz. : scrofulas, that owed their 

 existence to the influence of a so-called scrofulous acid that had been 

 secreted by pre-existing lymphatic glands in the lungs. Baillie, in 

 1794, opposed the idea that scrofulous nodes were of the same char- 

 acter as tuberculosis, and claimed that the large nodes in the lungs 

 were caused by the union of two or more of the smaller ones (miliary 

 tubercles). 



At the beginning of the present century, Bayle gave an exact de- 

 scription of the miliary tubercles and all the phases of their develop- 

 ment, as well as the part they play in forming larger tubercles. He 

 also recognized the relation existing between the tubercles in the 

 different organs of the body, and considered tuberculosis to be a gen- 

 eral disease whose origin was a tuberculous tendency. Laennec 

 adopted the same view in his work on the diseases of the heart and 

 lungs, published in 1818. He described the development of tubercu- 

 losis very clearly and accurately, but classed every chees}' deposit, 

 wherever found, as tuberculous, making cheesy degeneration the prin- 

 cipal characteristic of tuberculosis, a theory which was accepted by 

 many of his contemporaries. 



Vircliow has done much towards bringing order out of this chaos of 

 ideas. He proved that cheesy deposits were not characteristic of 

 tuberculosis alone, but that they might occur in all possible forma- 

 tions of an inflammatory nature under certaui conditions of nutrition. 

 He thus separated from the genuine tuberculous formations, all those 

 cheesy deposits that appear under certain inflammatory conditions, as 

 the scrofulous tumors of the lymph glands, in caseous pneumonia or 

 even in tumors of different kinds. 



Virchow believed in the infectious property of tuberculosis. He 

 claimed that the infectious element was dispersed over the organism 

 either by means of the blood-vessels, or by the extension of the dis- 

 ease by the development of new tubercles in the immediate vicinity 

 of older ones, the latter infecting the tissues in their immediate 

 vicinity. 



In 1857, Buhl advanced a new theory of tuberculosis, which had 



