Introduction of double inpregnation in the method of Grimelius.
D000818:Animals; D002415:Cats; D003584:Cytological Techniques; D004285:Dogs; D006168:Guinea Pigs; D008722:Methods; D051379:Mice; D051381:Rats; D013194:Staining and Labeling; D013961:Thyroid Gland / Q000166:cytology*