METHODS OF STAINING. 383 



2. Wash thoroughly in water until the section is blue. 



3. Dehydrate and mount. 



4. COUNTERSTAINS are used either with celloidin sections treated singly, or 

 with paraffin sections after they have been fastened on the slide. The three here 

 recommended are alcoholic solutions, and the method of using is the same for all. 

 If the sections are dried on the slide in an oven for three days, they will adhere 

 to the glass much more securely during the manipulations of counterstaining. 

 Lyons blue is less permanent than eosin and orange G. 



For staining paraffin sections on the slide it is convenient to have eight jars 

 or dishes large enough to hold a slide. The slide is transferred from jar to jar 

 in the order below, being allowed to remain in each jar a few minutes. The 

 very most scrupulous care is necessary to keep all the fluids clean, and it is indis- 

 pensable to filter them frequently; the sections on the slide catch and hold the 

 particles floating in the reagents when they are not clean. 



Order of jars: i. Xylol. 



2. Xylol. 



3. Xylol and absolute alcohol, equal parts. 



4. Absolute alcohol. 



5. Counterstain. 



6. Alcohol of 95 per cent. 



7. Absolute alcohol. 



8. Xylol. 



Eosin Formula: 2 per cent in 95 per cent alcohol. 



Orange G. Formula: i per cent in 95 per cent alcohol. 

 Lyons blue Formula: i per cent in 95 per cent alcohol. 



5. HEIDENHAIN'S IRON HEMATOXYLIN. 



Formula I: Iron alum 2 gm. 



Distilled water 100 c.c. 



II: Hematoxylin crystals i gm. 



95 per cent alcohol 10 c.c. 



Distilled water, to be added after the hematoxylin is dissolved in the 



alcohol , 90 c.c. 



(If the stain does not work, add 0.5 grm. lithium bicarbonate.) 



1. Place sections in the iron solution for from six to ten hours. (Specimens 

 hardened with Flemming's or Hermann's fluid require longer than specimens from 

 Zenker's or Tellyesnicky's fluid.) 



2. Wash quickly in water. 



3. Transfer to the hematoxylin solution for from twtlve to eighteen hours. 



4. Wash in tap-water. 



5. Decolorize in the iron solution. 



6. Wash thoroughly in tap-water. 



7. Dehydrate and mount. 



