128 VETBRINAEY OPHTHALMOLOGY. 



meningitis mostly. Still, with ascepsis and antisepsis 

 closely observed, there need be no hesitation in per- 

 forming this operation. 



A word or two anent the Ophthalmoscope and its 

 use. This instrument was the result of long and care- 

 ful investigation by Professor 11. Ilelmholtz of Berlin. 

 Was introduced to the scientific world in 1851. The 

 scope, as it exists to-day, consists of a mirror, either 

 plane or concave, with a perforation called the sight 

 hole. Also generally there is an object lens. The 

 mirror is the essential. Usually we use a lamp for 

 light, and have it held behind and to one side of the 

 eye we wish to examine. The examiner should keep 

 both eyes open, for the same reason that a sailor will 

 keep both open when using the telescope, and what- 

 ever may be seen by the other eye must be disregarded. 

 The first thing noticed will be a rec? reflex, where before 

 the introduction of the beam of light all seemed black. 

 Having succeeded this much, the student will try 

 and make up his mind finally that this particular 

 eye has no disc, but it is there, and that is the objective 

 point. Find the disc. Just when one decides to " let 

 go" and postpone the search, like a moon in a brilliant- 

 sky, the disc will sail into sight, and as -quickly sail 

 out of view. However, we have demonstrated to our own 

 satisfaction that it is there, and that gives one the needed 

 stimulus to go on and patiently endure disappointment 

 after disappointment, until, as always, success crowns 



