140 CLINICAL BACTERIOLOGY AND H^MATOLOGY 



Where the mere diagnosis of ringworm is in question, an 

 examination of the hair or scales after soaking in liquor 

 potassae is sufficient. The materials are placed in a drop of 

 the solution on a slide, and covered with a cover-glass; after 

 a quarter of an hour or so the specimen is carefully examined 

 under the microscope, using a J-inch lens and a small 

 diaphragm. The spores appear as spherical or oval, highly 

 refractile bodies, which can hardly be mistaken for anything 

 but fat globules. This possible source of fallacy may be 

 removed by soaking the hair in ether before applying the 

 liquor potassae. 



This is a rapid and simple method, but it does not enable 

 us to diagnose the nature of the fungus with certainty, except 

 in very typical cases. It is a very great advantage to employ 

 some method of staining'. These are by no means difficult, 

 though they are somewhat tedious. Two processes, both 

 modifications of Gram's method, will be given. They are not 

 difficult to apply, but are very slow. 



METHOD OF STAINING HAIRS, SCALES, ETC. 

 Requisites. i. Aniline gentian violet, carbol gentian violet, 

 or carbol fuchsin. 



2. Gram's iodine solution. 



3. Aniline oil, to which a little strong hydrochloric acid has 

 been added, two or three drops to a quarter of a test-tube 

 full of the oil. Prepare when required, and shake. 



4. Aniline oil. 



5. Xylol. This is not necessary unless the specimens are 

 to be kept permanently. 



6. Blotting-paper. 



7. Slides, cover-glasses, and balsam. 



Process. Take a broken hair or stump from the edge of 

 the suspected area (in the case of a longer hair, cut off all 

 the free portion, except a piece about J inch long). The 

 root and the part of the shaft next to it are all that are to be 

 examined. Several of these hairs can be stained at the same 

 time. 



Stain in watch-glass full of stain, or on a slide, for a 

 quarter of an hour, or longer the longer the better; it is an 

 advantage to warm the stain gently, and it will penetrate 

 better if the hairs have been previously washed in ether, though 

 this is not absolutely necessary. 



