no 



the paraffin. When the sections have become quite flat and smooth, 

 drain off the water and allow the slide to stand 2-3 hours, or better 

 over night, when a thin coating of Y\% collodion is given ( 67, a} 

 and they are placed in benzin. 



If the sections are large and thin, the coating with Y\% collo- 

 dion may be omitted ; in this case, let the sections stand 12-24 hours 

 after spreading, or for 2-3 hours if left in a warm place, as in an 

 incubator. 



The sections may also be straightened out by placing them on 

 a dish of water, such as the waste-jar, and hot water added slowly 

 until the sections extend, when, after the water has cooled, they 

 may be transferred to albuminized slides and carried on as before. 



PREPARATION FOR STAINING. 



68. Benzin. Both paraffin and collodion sections are trans- 

 ferred to benzin, which in the first case dissolves out the paraffin, in 

 the second serves to remove the clarifier still present in the tissue 

 and collodion. 



Leave paraffin sections in benzin until the paraffin is entirely 

 dissolved, requiring from a minute or so to 10-15 minutes, if $% 

 collodion was used in fastening the sections to the slide. 



Collodion sections should remain in the benzin 5-15 minutes or 

 longer, according to the thickness of the sections. Benzin may be 

 omitted and a proportionately longer time in the alcohol given. 



Sections may be left in benzin over night, and 2-3 days even 

 might do no harm, but it is better to proceed at once to the other 

 operations. 



69. Alcohol. Transfer from benzin to 95%alcohol to re- 

 move the benzin, leaving the section in the alcohol 5-10 minutes ; 

 or, if you wish, shorten the period to a minute or so by waving the 

 slide gently to and fro in the alcohol. A stay of a day or so in alco- 

 hol does no harm. Collodion sections generally require a longer 

 period than paraffin sections because of the collodion mass present 

 and their greater thickness. 



70. Water. Remove the 95% alcohol from the section by 

 plunging the slide into a jar of tap water and gently waving it 

 about in it. Should the stain to be employed be an alcoholic solu- 

 tion this step may be omitted. 



