206 BACTERIOLOGY OP THE EYE 



inflammation of the conjunctiva, with a painful swelling of the pre- 

 auricular gland and slight feverishness. This is usually rapidly 

 succeeded by an irritation of the iris, due to toxic absorption. This 

 latter condition, which is peculiar in that it occurs without any 

 change in the cornea, though that structure is permeated by the 

 toxin, not only occurs in streptococcal infections of the cornea, but 

 also in infections with the Pneumococcus (see Chapter III.). Experi- 

 ments on animals show that the streptococcal filtrate possesses in a 

 higher degree the power to produce a ' diffusion iritis ' Bardelli has 

 shown this by protracted instillations while a pneumococcal filtrate 

 does not produce any definite iritis in the rabbit. 



It must here be noted that in impetiginous eruptions of the face, 

 which commonly affect the conjunctiva, Streptococci are often found 

 in the secretions and in the cultures. This is especially the case 

 in persons with well-marked scrofula, and also in impetigo contagiosa. 

 The conjunctivitis is here secondary, and an extensive formation of 

 membrane is not commonly found in such cases, unless they are 

 associated with diphtheria bacilli. 



Characteristics of the Streptococcus Pyog-enes. 

 (PLATE IL, FIGS. IV. AND Via.} 



Streptococcus pyog cues (Streptococcus erysipclatis, septicus,pucrpe rails, 

 malignus, articulorum, scarlatinas us). 



In the secretion preparation the (Gram-positive) Streptococcus pyogenes varies 

 in appearance : 1. With regard to the size of the individual cocci. This is shown 

 very clearly by Fig. 42 and Fig. IV. on Plate II., which were both obtained from 

 similar cases of streptococcal diphtheria of the conjunctiva, and are under the 

 same magnification. 2. With regard to the arrangement of the individual cocci. 

 In Fig. 42 chain-formation is not at all obvious in many fields it would hardly be 

 noticed ; the double form is much more in evidence. When closely examined, we 

 see that chain formation does occur, but the chains are short and straight. In 

 Plate II. the chains are much clearer ; Diplococci are also seen. In the phagocytes 

 the cocci often lie together in the manner of Staphylococci. (Fig. 43 is drawn from 

 the pus of an orbital cellulitis, due to the breaking out of an empyema of the frontal 

 sinus; long chains were to be seen everywhere.) 



The diagnosis of a streptococcal conjunctivitis as against a staphylococcal is one 

 which requires some care. After having observed such cases for years, I have 

 never failed to find chains ; and a case such as that hi Fig. 42, where there might 

 be a difficulty if only a few fields were examined, is an extreme rarity in my 

 experience. The material should not be too much rubbed out, as then the natural 

 arrangement of the chains of cocci might be destroyed. It is well known that 

 Streptococci in animals sometimes do not form chains, so that on the conjunctiva 

 the possibility of a confusion cannot be entirely excluded. It is therefore advisable, 

 in pseudo-membranous or iiecrotic conjunctivitis in which there appears a strong 



