Celestine Blue B—Eosine-stained Intestine 219 



reflected from it to see whether or not the section is adherent to the glass. 

 If there is any air gap between the section and the glass, a brilliant mirror 

 will be formed, so that, in a preparation as simple as this, the slide had 

 better be thrown away. Those slides which are perfectly adherent are 

 warmed over a flame until the wax is melted and then dropped into a jar 

 of xylene, where they remain until a casual inspection shows the whole 

 of the paraffin to have been removed. They are put into another jar of 

 xylene for at least 5 min and then into a jar of equal parts of xylene and 

 alcohol for a further 5 min. This treatment is followed by 5 min in abso- 

 lute alcohol and then by direct transference to distilled water. After the 

 slides have been in distilled water for a few minutes, each slide should 

 be lifted and inspected to make sure that the water is flowing uniformly 

 over both the slide and section. If it tends to be repelled by the section 

 or a meniscus is formed around the section, this is evidence that the wax 

 has not been sufficiently removed, and the slide must be transferred first 

 to 96 per cent alcohol to remove the excess water, then to absolute alcohol 

 until perfectly dehydrated, and finally through absolute alcohol to xylene, 

 where it remains until the wax has been completely removed before being 

 brought down again as previously indicated. The slides may be taken 

 down through xylene and alcohol one at a time and accumulated in dis- 

 tilled water until they are required. When all slides have been accumu- 

 lated in distilled water, they are transferred to the celestine blue B stain- 

 ing solution for 1 min. One of the most useful features of this stain is that 

 it is almost impossible to overstain in it. It is even possible to leave sections 

 overnight without staining the cytoplasm to a degree that requires dif- 

 ferentiation. Each slide is now dipped up and down in the eosin solution 

 until a casual inspection shows the background to be yellowish pink. 

 The staining of the background in a case like this is entirely a matter of 

 choice; some people prefer a faint stain and others a darker stain, al- 

 though it must be remembered in judging the color that the section will 

 seem darker after it has been cleared than it does in water. 



As soon as the time required to produce the desired degree of staining 

 has been found by staining one slide, the remainder of the slides are 

 placed in the eosin solution, left the appropriate time, and then transferred 

 and left in distilled water until no more color comes away. The slides are 

 passed from distilled water to 96 per cent alcohol where they are left for 

 about 5 min. Then they are passed to fresh 96 per cent alcohol where they 

 are left for 5 or 6 min before being passed to absolute alcohol. The pur- 

 pose of using the 96 per cent alcohol is not to diminish diffusion currents 

 but simply to save diluting the absolute alcohol by passing slides directly 

 from water to it. After the slides have remained for 5 or 6 min in absolute 

 alcohol, a single slide is passed into the absolute alcohol-xylene mixture 

 for perhaps 2 min and then passed to xylene. On examination the slide 



