NATURE OF GLANDERS. 203 



tion of diseased lymphatic, must be a different thing from veritable 

 tuhercle of the lung, concerning the origin, and seat, and nature 

 of which such various opinions have at one time and another pre- 

 vailed among human pathologists, and which we now find de- 

 scribed by — perhaps the best authority we have — M. Louis, as 

 follows : — 



" It may now be inquired, in which of the various systems of organs com- 

 posing the lungs does the development of tubercles take place ? It results 

 from the researches of M. N. Guillot, that the ramifications of the pulmonary 

 artery, as far as they can be traced, are smooth, and free from tubercle ; so 

 that the opinion of those who place the primitive seat of the product in the 

 vessels is with difficulty tenable. On the other hand, according to the same 

 observer, if the bronchial ramifications of the tuberculous lung be cut open 

 as far as possible (the organ having been previously injected in such manner 

 that the fluid used shall have filled the entire web formed by the bronchial 

 arteries on the surface of the tubes) morhid changes are invariahhj detected in 

 these. The earliest stage of change appears in the form of a small whitish 

 speck, produced by a semi-transparent matter, of rounded or elongated shape, 

 and resembling the miliary tubercle pretty closely in colour and consistence, 

 or still more closely a small fragment of epidermis macerated in water. At 

 this period no vascularity is discoverable in the subjacent mucous membrane. 

 In the second stage the whitish semi-transparent matter is thicker and more 

 spread out, and the correspondent part of the parietes of the bronchial tube 

 is destroyed within variable limits. Hence it follows, that the produc- 

 tion of tubercles does not take place in the pulmonary vessels, but in the 

 bronchi — a doctrine which, as is well known, is that professed by Dr. Cars- 

 well. It is true, adds M. Guillot, that at the period when the morbid mat- 

 ter may be made the subject of examination in the bronchi, there have 

 already existed tubercles in the midst of parts of the organ inaccessible by 

 means of instruments ; but it is not fair to presume that the phenomena of 

 which I have just spoken may have equally well taken place in the rdtimate 

 culs-de-sacs of the respiratory system? It is^ however, matter of very little 

 consequence whether the primitive seat of a tubercle placed in the centre of 

 the lungs be the internal surface of a 'pulmonary vesicle., or the substance of 

 the icall separating each pair of cells : the extreme tenuity of these parts is 

 well known, and the attempt to localize a lesion at its origin in the midst of 

 such excessively delicate parts, could really lead to no useful result*." 



That the purulent matter contained in the suppurated pulmonary 

 tubercle of a glandered horse will, through inoculation, produce 



* Researches on Phthisis. By P. A. C. Louis, M.I). Translated from 

 the French by II. II. Walshe, M.D. 



