MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



fluorescent light in the visible spectrum. Basic and acidic fluoro- 

 chromes act specifically to stain certain cellular structures as do 

 the more common microscopic stains such as, for instance, 

 methylene blue and eosin. The colour and the intensity of 

 fluorescence depends on the relative basophilia and acidophilia of 

 the individual cells, and upon the nature of the particular fluoro- 

 chrome. 



Fluorochromy may be employed with advantage in the study of 

 living organisms: for instance, uranin, a non-toxic stain, may be 

 injected into mice and frogs and the living organs can be studied 

 without interfering with their functioning. Fluorochromy is also 

 of practical importance for the demonstration of diphtheria bacilli, 

 tubercle and leprobacilli, malaria, etc., as well as for virus research. 



(b) EQUIPMENT REQUIRED 



Contrary to the generally held belief, the apparatus required for 

 fluorescence microscopy is fairly simple and inexpensive. A special 

 microscope is not required. 



1. B.T.H. Mazda Mercury Vapour Lamp (box type) ME 250 



w/50/5. 



2. A simple convex lens to project the image of the light source 

 through a suitable blue filter to the microscope mirror. The lens 

 and light source should be encased with a black hood to prevent 

 scattering of the rays. 



3. A yellow filter which is placed in the oculars of the micro- 

 scope to prevent any harmful effect of ultraviolet light to the 

 microscopist's eyes. For this purpose Ilford's minus blue Micro 4 

 is recommended. 



It is, of course, essential that fluorescence microscopical examin- 

 ations must be carried out in a darkroom to be successful. It has 

 been stated that microscope slides of special glass are necessary 

 for fluorescence microscopy, but provided they are not more than 

 1-3 mm. in thickness ordinary microscopic slides have been found 

 quite satisfactory. 



316 



