xiv INTRODUCTION 



example, to have a drawing made from a pneumonic sputum, as in the 

 latter the appearance can be different from that of the conjunctival 

 secretion. 



For diagnosis I consider that coloured plates are better than micro - 

 photographs. Though the latter are very valuable yet even with the 

 best technique many fine details do not appear so distinct as to make 

 the picture absolutely clear I need merely refer to the fact, for 

 example, that we hardly possess an absolutely good photograph of 

 a secretion preparation containing Koch-Weeks bacilli. 1 Either from 

 over-exposure, or from over-staining (to make them more obvious), the 

 bacilli are too thick, and many of the finest rods are not represented. 

 It is also a great advantage to represent the contrast of the Gram 

 stain, and to emphasize from the first the reaction of the bacteria to 

 this diagnostic method which is the most useful in everyday work. 

 In other ways I do not undervalue micro-photography, as is seen from 

 the text of this book. 



I have attempted to describe the organisms which are exclusively or 

 principally pathogenic for the eye as fully as the available material 

 would allow ; and with regard to the others, while I have emphasized 

 all ophthalmic work in the general bacteriological literature, I have 

 only done so with regard to the most important. Those who would 

 study the latter fully must naturally make use of the bacteriological 

 text and handbooks. 



The subdivision of the material presented some difficulty. Anyone 

 who inquires into ophthalmic bacteriology, or would like to determine 

 the importance to be ascribed to any finding, will wish to ascertain 

 not only where and with what results the bacterium is to be found in 

 ophthalmology, but also to observe the clinical appearances, and 

 decide what is the cause of infection in the particular case. 



The easiest way would have been to have gone through the whole 

 material twice, once according to the bacteria, and again according to 

 the clinical appearaces. This would, however, make the field too 

 wide, and cause numerous repetitions. 



Under these circumstances I have chosen a clinical division, for 

 I thought that a purely bacteriological one would have been more 

 difficult, and would have been less likely to arouse the interest and 

 co-operation of ophthalmic surgeons. I have not held rigidly to this 

 principle, for just as the clinical picture sometimes is the most 

 important, so sometimes the one point of view, and sometimes the 



1 The best which I know of are by Heim. 



