Staining 447 



junctivitis] is characterized by the constant presence in the 

 conjunctival secretions of a small bacillus seen for the first 

 time by Koch, but studied some years later by Weeks, and 

 now known as the bacillus of Weeks." 



Further descriptive and clinical information can be found 

 in a paper by Weeks, "The Status of our Knowledge of the 

 J^tiological Factor in Acute Contagious Conjunctivitis."* 



Morphology. The organism is very tiny and is said to 

 bear some resemblance to the bacillus of mouse-septicemia. 

 It measures i to 2 X 0.25 ^ (Weeks). The length is more 

 constant in individuals found in the pus than those taken 



Fig. 140. The Koch- Weeks bacillus in conjunctival secretion. Magni- 

 fied 1000 diameters (Rymowitsch and Matschinsky). 



from cultures. In cultures the organisms are longer and 

 more slender. Involution forms of considerable length and 

 of irregular shape also occur. No spores are observed. The 

 organism has no flagella and is not motile. 



Staining. Weeks found that the organism stained well 

 with watery solutions of methylene-blue, basic fuchsin, or 

 gentian violet. The color is fainter than that of the nuclei 

 of the associated pus-corpuscles, and is much less intense in 

 old than in fresh cultures. It is readily given up when 

 treated with alcohol or acids. Morax found that the bacilli 

 did not retain the color in Gram's method. 



''New York Eye and Ear Infirmary Reports," vol. in, Part i, 

 Jan., 1895, p. 24. 



