398 STAINING MICROSCOPIC OBJECTS [Ch. XI 



hours. Wash well with water, but one must be careful in treating 

 these sections, as they have no collodion mantle to protect them. 



(3) Stain 15 to 30 seconds with picro-fuchsin of one-fourth 

 strength (§645). Dehydrate with 95% and if necessary absolute 

 alcohol. Clear in carbol-xylene and mount in acid balsam (§ 547). 

 The elastic tissue will be black or blue black. Mucus will be carmine 

 or rose red; white fibrous tissue will be magenta red; muscle, epithe- 

 lium, and blood will be yellow. 



§ 647. Eosin methylene blue. — One of the best objects for this 

 stain is a hemolymph gland. Such a gland is easily and surely found 

 by a beginner if he takes the heart and lungs of a veal. In the fat 

 around the heart and behind the pleura will be found red bodies look- 

 ing almost like blood clots. Remove carefully; fix in Zenker's fluid 

 or mercuric chlorid (§ 579, 592). Section by the paraffin method, 

 make the sections 5/x and 10^ thick. Use collodion for insuring the 

 fixation to the slide (§ 622). Stain the sections 5 minutes in alcoholic 

 eosin (§ 563). Wash off the eosin stain with water. (This is an 

 exception to the generalization in § 638.) 



Stain in methylene blue (§ 580) one-half to 5 minutes. Rinse well 

 in tap water. Dehydrate with neutral 95 % alcohol and with absolute 

 alcohol. Work rapidly with only one slide at once. Clear with pure 

 xylene, mount in neutral balsam (§ 546). All nuclei should be blue, 

 and all red blood corpuscles bright eosin red. If one is successful 

 this is a most striking and instructive- preparation. Spleen is also 

 very instructive. 



Eosin-methylene blue staining is also excellent for demonstrating 

 mucus. 



Do not forget that mercury is liable to be present in sections of 

 tissue fixed with any mercuric fixer. Remove it with iodized alco- 

 hol (§ 576). This should be done before the staining. One can tell 

 whether the tissues contain mercury by looking at the unstained 

 sections. The mercury looks black by transmitted light, white by 

 reflected light. Seen by transmitted light, the substance is often in 

 the form of delicate black pins. 



§ 648. Iodin stain for glycogen. — Use tissue fixed in 95 % or abso- 

 lute alcohol. Cut by the paraffin method. Mount the sections in 



