272 



TUBERCULOSIS 



manner at the periphery, occasionally also in epithelioid cells 

 and in leucocytes. 



The above statements, however, apply only to tuberculosis 

 in the human subject, and even in this case there are exceptions. 

 In the ox, on the other hand, the presence of tubercle bacilli 

 within giant-cells is a very common occurrence ; and it is 

 also common to find them in considerable numbers scattered 

 irregularly throughout the cellular connective tissue of the lesions,. 

 even when there is little or no caseation present (Fig. 81). 



In tuberculosis in the horse and in avian tuberculosis the 

 numbers of bacilli may be enormous, even in lesions which are 



not specially acute ; and 

 considerable variation 

 both in their number and 



4N9 1 ^ in their site is met with 



in tuberculosis of other 

 animals. 



In discharges from 

 tubercular lesions which 

 are breaking down, tu- 

 bercle bacilli are usually 

 to be found. In the 

 sputum of phthisical 

 patients their presence 

 can be demonstrated al- 

 most invariably at some 

 period, and sometimes 



FIG. 82. Tubercle bacilli in urine ; showing their numbers are very 



one of the characteristic clumps, in which j (for method of stain _ 



tney oiten occur. . r\**\ o i 



Stained with carbol-fnchsin and methylene- ing, see p. 10/). Several 



blue. xlOOO. 



examnatons may, 

 ever, require to be made ; 



this should always be done before any conclusion as to the non- 

 tubercular nature of a case is come to. In cases of genito-urinary 

 tuberculosis they are usually present in the urine ; but as they 

 are much diluted it is difficult to find them unless a deposit is 

 obtained by means of the centrifuge. This deposit is examined 

 in the same way as the sputum. The bacilli often occur in little 

 clumps, as shown in Fig. 82. In tubercular ulceration of the 

 intestine their presence in the faeces may be demonstrated, as 

 was first shown by Koch ; but in this case their discovery is 

 usually of little importance, as the intestinal lesions, as a rule, 

 occur only in advanced stages when diagnosis is no longer a 

 matter of doubt. 



