256 SCROFULA — TUBERCULOSIS. 



as capable of resulting in the production of a material identical 

 with tubercle ; this is, however, doubtful, unless the scrofulous 

 diathesis exists. Caseation is something different from tubercle. 

 It seems, from comparison of facts and data, that tuberculosis 

 may be propagated under favourable conditions from the 

 actually diseased to the healthy. These conditions are close 

 and intimate cohabitation, partaking of milk from tuber- 

 culous animals, and the using of their flesh as food. The 

 latter probably require further confirmation. All influences 

 which tend to depress and lower the general vital activities 

 in animals seem to render them more liable to develop tuber- 

 culous diseases. Under this group we must rank indifferent 

 food, bad sanitary conditions — particularly defective ventilation 

 — over-work in contaminated atmospheres, previous disease, 

 jjrolonged lactation, etc. These influences are all more 

 powerful when operating on animals in confinement. 



2. Taherde. — As respects the direct or immediate causation 

 of the tubercle, several operating agencies have been accre- 

 dited Avith the power of production : (1) Tubercle has been 

 regarded as merely the local expression of that constitutional 

 cachexia or diathesis known as the scrofulous. (2) That it 

 arises from local irritation of that particular tissue, the adenoid, 

 in which it is largel}^ found, apart from any constitutional ten- 

 dency. (3) That it always arises as the product of an infective 

 action proceeding from some j)i'eviously existing centre of 

 inflammation, poisoning the lymph and blood-streams, and 

 developing a specific inflammation. This is the view largely 

 supported by experimentation, but it seems to need modi- 

 fication. 



Anatomical Characters, a. General Features. — The typical 

 tubercle, grey granulation or miliary tubercle, may be regarded 

 as a non-vascular, round or roundish microscopic body, well- 

 defined, of variable consistence and greyish colour. These 

 are either discrete or aggregated in masses of variable size, 

 or they may bo infiltrated throughout the structures where 

 situated. 



Yellow tubercle, so-called, is probabl}'- degenerate common 

 inflammatory product, or changing tubercular matter, which 

 may have become mingled in the caseous mass. This 

 adventitious material is found on the free surface of mucous 



