SPECIAL FORMS OF CONJUNCTIVAL INFECTION 237 



methylene blue films. Possibly in certain secretions this may be a fixed 

 characteristic. 



I must here state that after a considerable experience I consider that this coffee- 

 bean form does [not indicate any special variety, particularly any pathogenic form, 

 as one might suppose from the emphasis laid upon it by Michel with regard to his 

 so-called Trachoma cocci, and by Wildbrand, Saenger, and Staehlin in follicular 

 conjunctivitis. This diplococcal form is common to the whole group of the Stapliy- 

 lococci, and is especially noticeable in the white, non- virulent, common form when 

 growing on the conjunctiva. Gram-positive coffee-bean shaped Diplococci can 

 generally be diagnosed as Staphylococci, 1 and a causal function should not be 

 lightly attributed to them, as in the majority of cases they represent a secondary 

 growth, not the original or sole infection. 



The examination of a smear preparation does not allo r us to diagnose which 

 variety of the large family of the 8taj)hylococci is present, though it may be stated 

 that the typicar*grape-like clusters appear more frequent in the strongly pathogenic 

 forms, while the Gram-positive Pseudo-gonococci (meaning organisms resembling 

 the Gonococcus when stained by the ordinary aniline dyes) more frequently occur 

 in the common saprophytic forms. 



Even when in a culture there is only one form present (e.g., the slightly patho- 

 genic Stapliylococcus albus non-liquefaciens, or Micrococcus candicans), quite 

 a considerabfe variation in the size and arrangement of the cocci in the secretion 

 preparation may be apparent. 



The common cultural characteristics of the Stapliylococcus pyogenes aureus, 

 albus, and citreus (the latter of which is the rarest on the conjunctiva) will be found 

 in the chapter on the ' Normal Conjunctiva,' and in the tables at the end. The 

 pyogenic forms liquefy gelatine with acid formation ; the saprophytes do not, 

 though their agar and serum cultures very much resemble those of the albus 

 pijogenes. In the individual colonies the commonest white saprophytes show 

 a concentric marking and a central prominence ; this, however, is not constant. In 

 many cases it resembles the variety known as the Micrococcus candicans. 



Besides the common representatives of the group of Staphylococci, single 

 colonies of the rarer allied forms are occasionally met with, but never in profusion. 

 They are of very little practical value. I have referred to them in the chapter on 

 the ' Normal Conjunctiva ' (see p. 36). 



In the secretions of other kinds of catarrh e.g., in trachomatous secretions we 

 not uncommonly see very large Gram-positive Diplococci, in which, when the 

 staining is favourable, the clear separation line is very well marked (see Plate II., 

 Fig. V., b). These may belong to the common white variety. They may, however, 

 be Gram-positive Sarcince, especially when they lie in fours ; the Sarcinez in the 

 conjunctiva tend to occur less in packet forms than in fours or in couples (this is 

 also the case for the Gram-negative Sarcince, see Plate II., Fig. III., c). Capsulated 

 tetrads should suggest Tetragenus (Sarcina tetragena, Migula), which I have 

 obtained a few times. 



This organism is of no practical importance in ophthalmic practice (Valude found 

 it in the secretion of a case of dacryocystitis neonatorum). According to Migula, 

 tetrads and Sarcina forms can develop out of Staphylococci. 



On the normal conjunctiva and lid-margins the white StapTiylococci are 

 commonly found ; the aureus is the most generally met with on the catarrhal 

 membrane. This is a repetition of what we find in the skin in acute eczema, and 

 in the lids in blepharitis, where with the inflammation the aureus always tends to 

 come more and^nore to the fore. There are several possible explanations for this : 

 either the inflammation affects those people who have the aureus present, and 



1 It is much rarer for the Streptococcus to shoAV this diplococcal form. 



