DESCRIPTION OF PLATE XI. 

 Bacillus tuberculosis. 



The figures in this plate represent the bacilli of tuberculosis in 

 different animals, examined under the same conditions of amplifica- 

 tion and illumination. x 1200. Lamp-light illumination. 



FlG. 1. Bacilli in pus from the wall of a human tubenmlar cavity. In 

 this specimen the bacilli are shorter than those in tubercular sputum, 

 and are very markedly beaded. 



FIG. 2. Bacilli in pus from a tubercular cavity from another case in man. 

 They are present in the preparation in enormous numbers. The proto- 

 plasm occupies almost the whole of the sheath, and the bacilli are 

 strikingly thin and long. 



FlG. 3. Bacilli in sputum from an advanced case of phthisis, showing 

 the ordinary appearance of bacilli in sputum ; some beaded, others 

 stained in their entirety ; occurring both singly and in pairs, and 

 in groups resembling Chinese letters. 



FlG. 4. Bacilli in a section from the lung in a case of tuberculosis in man. 

 The bacilli in human tuberculosis are found in, and between, the tissue 

 cells ; and sometimes, as in equine and bovine tuberculosis, in the 

 interior of giant cells, but not so commonly. 



FIG. 5. From a cover-glass preparation of the deposit in a sample of milk 

 from a tubercular cow. The bacilli were longer than the average 

 length of bacilli in bovine tissue sections, and many were markedly 

 beaded. 



FIG. 6. From a section of the brain in a case of tubercular meningitis in a 

 calf, showing a giant cell containing bacilli with the characters usually 

 found in sections of bovine tuberculosis. 



FIG. 7. From a section of the liver of a pig with tubercle bacilli at the 

 margin of a caseous nodule. 



FIG. 8. From a cover-glass preparation of a crushed caseous mesenteric 

 gland from a rabbit infected by ingestiori of milk from a cow with 

 tuberculosis of the udder. 



FlG. 9. From a section of lung in a case of equine tuberculosis, showing a 

 giant cell crowded with tubercle bacilli. 



FIG. 10. From a section of lung from a case of tuberculosis in the cat, with 

 very numerous tubercle bacilli. 



FIG. 11. From a cover-glass preparation of a crushed caseous nodule from 

 the liver of a fowl, with masses of bacilli. These are for the most part 

 short, straight rods ; but other forms, varying from long rods to mere 

 granules, are also found. 



FIG. 12. From sections of the liver and of the lung in a case of tubercu- 

 losis of a Khea. Isolated bacilli are found, as well as bacilli packed in 

 large cells, colonies of sinuous bacilli, and very long forms with terminal 

 spore-like bodies and free oval grains. 



The preparations from which these figures were drawn were all 

 stained by the Ziehl-Neelsen method, with the exception of the 

 first, which was stained by Ehrlich's method. 



