12 BACTEEIOLOGY OF THE EYE 



1. Mast Cells are often found in large numbers, especially in chronic inflamma- 

 tions. Their shape conforms to that of the connective tissue around ; in the sclera, 

 for instance, they are often elongated, so that sometimes it is only their processes 

 which appear in a section. The stained protoplasmic granules, especially when 

 derived from a breaking-down mast cell, at first glance are very like cocci, and take 

 on Gram's stain. On closer examination the variable size of the granules and their 

 connexion with a cell can be noted. 



2. Pigment. Retinal pigment, in the form of crystalline granules or rods, can 

 be found in various parts of the diseased eye. The beginner may sometimes 

 mistake this, as it often takes up a little aniline dye. Careful observation will 

 prevent such an error.' The granules are yellowish, transparent, and strongly 

 refractive. This is much better appreciated in daylight than in lamplight, when 

 everything looks yellowish. 



3. All Solutions must be Quite Free from Organisms. When staining 

 sections of the eyeball, especially by the Gram-Weigert method, and on the slide, 

 the sclera and optic nerve- sheath may fray out, and in the cracks incidental 

 organisms may collect. In old lithium- car mine solutions cocci often occur. Filter 

 every solution carefully. 



Capsule-Staining. 



(a) KleWs method : 



1. In alcoholic watery methylene blue (methylene blue, 1 ; alcohol, 10 ; 



water, 100) sections are warmed until the solution boils. 



2. Wash with water. 



3. Five seconds in solution of fuchsin, 1 ; alcohol, 10 ; water, 100. 



4. Wash in water and mount. 



Bacilli, blue ; capsules, red. Usually a good stain. 



(b) Friedldnder 's method : 



1. Two minutes in 1 per cent, acetic acid. 



2. Wash and dry. 



3. Few seconds in anilin-water-gentian-violet. 



4. Wash dry, etc. 



Bacteria, dark violet ; capsules, light violet. 



(c) Johne s method : 



1. One to two minutes in a warm watery solution of methyl or 



gentian violet. 



2. Wash with water. 



3. Decolorize for ten seconds in 1 to 2 per cent, acetic acid. 



4. Wash with water ; examine in water. 



Result same as (b). 



(d) Kaufmann's method : 



1. Stain for several hours with cold Loffler's methylene blue, or for 



two hours in the oven. 



2. Wash with alkaline water (1 or 2 drops normal potash or soda in a 



large watch-glass of water). 



3. Dry. Stain with AgNO 3 per cent, for two minutes. 



4. Wash again with alkaline "water. 



5. Stain for thirty seconds in fuchsin (1 part of saturated alcohol 



solution to 20 parts of water). 



6. Wash for a few seconds in alkaline water. ; 



7. Dry and mount. 



The organisms are blue, the capsules red. 



