148 BACTERIOLOGY. 



The cover-slips are prepared in the usual way, or the 

 fixing may be accomplished with absolute alcohol in- 

 stead of high temperatures. The preparation is then 

 held for two minutes in chloroform, then washed off in 

 water, then placed for from one-half to two minutes in 

 a 5 per cent, solution of chromic acid ; again washed 

 off in water, and now stained in carbolic fuchsin. In 

 the process of staining, the slip is taken by the corner 

 with the forceps, and carbolic fuchsin is dropped upon 

 the side containing the spores. It is then held over the 

 flame until it boils, and then held some distance above 

 the flame for one minute. The staining fluid is then 

 poured off and the preparation is completely decolorized 

 in 5 per cent, sulphuric acid, again washed off in water, 

 and finally stained for thirty seconds in the watery 

 methylene-blue solution. The spores will be red, the 

 body of the cells blue. 



In this method the object of the preliminary ex- 

 posure to chloroform is to dissolve away any crystals 

 of lecithin, cholesterin, or fat that may be in the prepa- 

 ration, and which when stained might give rise to con- 

 fusion. 



It must be remembered that there are conspicuous 

 differences in the behavior of spores of different bac- 

 teria to staining methods. Some stain readily by either 

 of the methods especially devised for this purpose, 

 while others can hardly be stained at all, or only with 

 the greatest difficulty, by any of the known processes. 



LCEFFLER'S METHOD FOR STAINING FLAGELLA. 

 For the demonstration of the locomotive apparatus 

 possessed by motile bacteria we are indebted to Locffler. 

 By a special method of staining in which the use of 

 mordants played the essential part, he has shown that 



