186 BACTERIOLOGY OF THE EYE 



contact, and were never elongated. The cocci were Gram -positive, and had 

 wide baggy capsules, which were easily stained by the methods of Klett or of Heirn. 

 Cultures. Bluish-grey colonies the size of a pin's head grow on gelatine at 25 C. 

 without liquefaction. In bouillon a slight transient opacity, accompanied by a 

 slight slimy deposit, occurs after twenty-four hours. Growth is better in grape- 

 sugar bouillon ; in blood bouillon the blood sinks in clumps to the bottom, with 

 partial haemolysis. On agar grey colonies grow to the size of a pin's head or larger; 

 these, when they are closer together, form a slimy scum on the surface. Blood- 

 agar clears in the vicinity of the individual colonies, and takes on a greenish colour. 

 On blood-serum growth is analogous to that on agar, but is not so vigorous. The 

 best growth is obtained on litmus-nutrose agar. Milk coagulates in four days. 

 Litmus lactose becomes slightly red in forty-eight hours. On potatoes no growth. 

 No gas formation. Anaerobic growth is good. Cultures kept moist retain their 

 vitality for a long time. Pathogenicity for mice is very considerable : O'l c.cm. of 

 grape-sugar bouillon killed a mouse in twelve hours, with serous effusions and 

 enlargement of the spleen. In the blood and in the exudate capsulated Dijilococci 

 of varying size and cocci in short chains were found, but no lancet forms. 



FIG. 35. STREPTOCOCCUS Mucosus. FIG. 36. CONJUNCTIVAL SECRETION 



AGAR CULTURE FROM THE CONJUNCTIVA. WITH STREPTOCOCCUS Mucosus. 



A drawing from a preparation by "VVirtz. 



Occasionally thick rods were seen; these Wirtz held to be cocci in close apposition, 

 young forms in the act of dividing. In cultures the capsules were best shown by 

 Giemsa's stain. 



Wirtz states that in secretions and in the blood the absence of lancet forms 

 differentiates this organism from the Pneumococcus. However, he rightly states 

 that in cultures the distinction is more difficult on account of the tendency of 

 many strains of Pneumococci to grow in chains. The Streptococcus mucosus grows 

 best on grape-sugar bouillon and litmus-nutrose agar ; it forms large colonies on 

 agar and on serum of a clear gelatinous consistency (this occasionally occurs with 

 the Pneumococcus}. The method of differentiation by means of blood media, 

 emphasized by Schottmiiller, is of no use when dealing with this variety. 



Seeing that the Streptococcus mucosus is considered as the pathogenic agent in 

 many cases of inflammation of the lungs, sepsis, meningitis, and otitis media, and 

 as it had considerable pathogenicity for animals in his case, Wirtz considered it to 

 be the cause of the peculiar secretion, and recommended that this organism be 

 looked for in all these cases. As the allied ' Leukonostoc ' sugar became gelatinous, 

 Wirtz considered whether a secretion particularly rich in carbohydrate might not 

 be present in his case. Mucin was, however, only present in very small amount, 

 and sugar tests were quite negative. The Streptococms mucosus did not produce 

 a slimy reaction when tried in various sugars. In the nose and in the throat of 

 healthy individuals the Stre2)tococcus mucosus is sometimes found. 



