EXPERIMENTAL INOCULATION 



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down, tubercle bacilli are usually to be found. In the sputum 

 of phthisical patients their presence can be demonstrated almost 

 invariably at some period, and sometimes their numbers are very 

 large (for method of staining, see p. 105). Several examinations 

 may, however, require to be made ; this should always be done 

 before any conclusion as to the non 7 tubercular nature of a case 

 is come to. In tubercular meningitis the bacilli can often be 

 found in the cerebro-spinal fluid obtained by lumbar puncture. 

 In cases of genito-urinary 

 tuberculosis they are 

 usually present in the 

 urine; but as they are 

 much diluted it is dim- , 

 cult to find them unless jj 

 a deposit is obtained by ;jB 

 means of the centrifuge. Im 

 This deposit is examined St 

 in the same way as the W 

 sputum. The bacilli often 

 occur in little clumps, as 

 shown in Fig. 78. In 

 tubercular ulceration of 

 the intestine their pres- 

 ence in the feces may be 

 demonstrated, as was first Fig. 78. — Tubercle bacilli in urine ; showing 

 shown bv Koch ■ but in 01ie °* tne characteristic clumps, in which 

 . . * , , . '. they often occur. 



this case their discovery stained with carbol-fuchsin and methylene- 

 is usually of little im- blue. xlOOO. 

 portance, as the intestinal 



lesions, as a rule, occur only in advanced stages when diagnosis 

 is no longer a - matter of doubt. 



Experimental Inoculation. — Tuberculosis can be artificially 

 produced in animals in a great many different ways — by injection 

 of the bacilli into the subcutaneous tissue, into the peritoneum, 

 into the anterior chamber of the eye, into' the veins ; by feeding 

 the animals with the bacilli ; and, lastly, by making them inhale 

 the bacilli suspended in the air. 



The exact result, of course, varies in different animals and 

 according to the method of inoculation, but we may state 

 generally that when introduced into the tissues of a susceptible 

 animal, the bacilli produce locally the lesions above described, 

 terminating in caseation ; that there occurs a tubercular affection 

 of the neighbouring lymphatic glands, and that lastly there 

 may be a rapid extension of the bacilli to other organs by the 



