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. 



Fia. 1. — Bacilli in pns from the wall of a human tubercular cavity. In 

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

 and are very markedly beaded. 



Fie. 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. 



Fig. 3. — Bacilli in sputum from an advan.ced case of phthisis, showing 

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

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

 in groups resembling Chinese letters. 



Fig. 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. — B'rom a cover-glass preparation of the deposit in a sample of milk 

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

 lengrli 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 ingestion of milk from a cow with 

 tuberculosis of the udder. 



Fig. 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 Ehea. Isolated baciUi 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. 



