652 GENERAL STAINING 



ANATOMICAL STAINS 



1289. Basic fuchsin is one of the best for lignified and suberised 

 tissues. Prepare by adding a 5 per cent, alcoholic solution to 

 strong ammonia (0-880) so long as the solution remains colourless 

 or has merely a pale straw colour. To use (1) immerse freehand 

 sections in the stain for some time and then wash in 95 per cent, 

 or absolute alcohol until the correct depth of colour has been 

 produced, then clear in clove oil (Zimmermann). (2) Dip 

 sections into the stain for a few seconds and then expose to allow 

 the ammonia to evaporate ; when the correct colour has been 

 reached dehydrate rapidly and clear (Bond, Trans. Roy. Soc. 

 Edin., Ivi., 1931, p. 695). 



1290. Heidenhain's Iron Haematoxylin, followed by safranin 

 as a counterstain, is a good combination for general anatomical 

 purposes, and especially for wood sections. Congo red (saturated 

 aqueous solution) is superior to safranin as a counterstain for 

 bark. 



1291. Safranin and Delafield's Haematoxylin. Stain in 

 safranin three to twenty-four hours (or less) and differentiate in 

 50 per cent, alcohol, acidulated if the stain comes out too slowly, 

 until the parenchyma is pink, while the lignified tissues are red. 

 Wash in distilled water. Stain in Delafield's haematoxylin until 

 the stain is sufficiently dark. Wash in several changes of slightly 

 alkaline water (tap water or distilled water with a trace of 

 ammonia). A poor contrast results from insufficient washing. 

 Collenchyma and plastids purple-blue ; lignified tissues, cuticle, 

 cork or nuclei red. 



1292. Heidenhain's Iron Haematoxylin and Eosin (or Ery- 

 throsin). Stain in the haematoxylin and dehydrate to 70 per cent, 

 alcohol. Counterstain with eosin or erythrosin. Cellulose, etc., 

 pink ; lignified tissues and nuclei black. Depending upon the 

 degree to which the differentiation is carried, the haematoxylin 

 may stain the whole wall of lignified tissue or be restricted to the 

 middle lamella. 



1293. Delafield's Haematoxylin and Erythrosin. Stain in 

 haematoxylin and afterwards stain thirty seconds to one minute 

 in erythrosin. Orange G is also a good stain to follow Delafield's 

 haematoxylin. 



1294. Safranin and Light Green. Stain in safranin and 

 differentiate. Stain in a solution of light green in 90 per cent, 

 alcohol for ten to thirty seconds. The light green stains vigorously 

 and also reduces the safranin. Pass rapidly through 95 per cent, 

 and absolute alcohols and clear in xylol. The cellulose tissues 

 stain green. The light green can also be dissolved in clove oil. 

 Stain not more than thirty seconds, rinse with clove oil and wash 

 with xvlol. 



