114 A MANUAL OF BACTERIOLOGY 



(b) Moeller's method. Prepare the cover-glass or slide specimen 

 in the ordinary way. Treat with absolute alcohol for two minutes, 

 and then with chloroform for two minutes. Wash in water and 

 treat with a 5 per cent, solution of chromic acid for two minutes, 

 wash, and then stain with warm carbol-fuchsin for ten minutes. 

 Wash, decolorise carefully in 1 per cent, sulphuric acid, again wash 

 and counter-stain with Loffler's methylene blue for one minute ; 

 wash, dry, and mount. Some organisms, such as the B. mesen- 

 tericus, stain better if treated with the chromic acid for five to ten 

 minutes. 



Flagella Staining 



Many organisms possess delicate protoplasmic processes 

 flagella in greater or less number ; but these are not 

 visible when the organism is examined in the living con- 

 dition (except by the use of dark-ground illumination), 

 nor when the ordinary staining methods are employed. 

 In order to demonstrate them it is necessary to make use 

 of some special method, in which a mordant is essential. 

 One of the earliest devised was that of Loffler, which with 

 care gave fair results. It is not, however, nearly so 

 satisfactory as some more recent ones, so is omitted. 



For all methods of flagella staining the cover- glasses or 

 slides must be absolutely clean, the cultures recent, and 

 the growth sufficiently diluted to obtain the organisms in 

 an isolated condition. 



(a) Stephens's method. This is a modification of the well-known 

 Van Ermengem method, 1 and has been communicated to the writer 

 by Dr. J. W. W. Stephens. 



To clean slides. Rub the slides with a clean cloth and place on 

 a piece of clean wire gauze and heat with a smokeless flame for 

 some minutes (by this means grease is completely removed). 

 Remove the slides when cool, not before. 



To make the suspension. All methods are unsatisfactory. Rub a 

 little of the culture in a small drop of tap-water in a watch-glass. 

 Then transfer a drop with the smallest possible platinum loop to 

 a minute drop of water on the slide. Mix and spread with the 



1 Cenlr. f. Bakt., xv, 1894, p. 969. 



