DISSEMINATION OF OPHTHALMIA BY FLIES 277 



Koch-Wci'ks bacillus (perhaps also influenza bacillus), and the 

 pneumococcus (in Egypt the gonococcus also, rarely snbtilis). 

 Other pathogenic conjuncti vital organisms' only exceptionally 

 occur." And, further, " Gonococci and Koch-Weeks bacilli evi- 

 dently lose their power of causing a conjunctivitis very slowly 

 indeed, and are very independent of any disposition." His state- 

 ment that "on account of their gi-eat virulence and the marked 

 susceptibility to them, a very small number suffices," is important 

 in considering the relation of flies to the spread of the disease, 

 although, as he remarks, every infection does not produce the 

 disease. The fact that the Koch-Weeks bacillus cannot resist 

 dryness cannot be urged as an argument against the spread of the 

 infection by flies, or the same would apply to the typhoid bacillus, 

 whose carriage by flies is proven. Axenfeld mentions L. Miiller 

 and Lakah and Khouri as advocating the view that flies may spread 

 the infection more readily. In view of the fact that, as the same 

 author states, " Koch-Weeks conjunctivitis is to be classed with the 

 most contagious infectious disease which we know of," it is im- 

 portant that the role of flies should be recognised. 



Notwithstanding the occurrence in temperate climates of flies 

 in less numbers than in such countries as Egypt, it would be well 

 to bear in mind the probable influence of flies in cases of acute 

 conjunctivitis, such as those described by Stephenson (1897) in 

 England. The sole difference between the disease in Egypt and 

 in England is, as Dr Bishop Harman points out to me in a letter, 

 that " the symptoms produced (in Egypt) are, from climate and 

 dirtiness of the subjects, more severe, and that there is found 

 a greater number of cases of gonorrhoea! disease than in England " ; 

 and, I would add, a far greater number of flies. This disease is 

 eminently suited for dissemination by flies, both on account of the 

 accessibility of the infectious matter in the form of a purulent 

 discharge from the eyes and on account of the flies' habit of fre- 

 quenting the eyes. 



A number of writers, among whom are Braum (1882), Deme- 

 triades (1894) and German (1896), refer to the agency of flies in 

 communicating gonorrhoea! and similar infections of the eye. 



1 In this connection he states (p. 2B6) : "We can make the general statement 

 that the Staphylococcus in the conjunctiva is not contagious." 



