Cutting, Staining, and Mounting Vegetable Sections 173 



While cutting keep the knife well wetted with methylated 

 ;spirit, and, as the sections are cut, put them into spirit ; no 

 water must come near them. When ready, stain the sections 

 in a strong solution of acid aniline green in spirit for 

 several hours. Then just rinse in absolute alcohol, clear 

 in clove-oil, and mount in Canada balsam. 



Transverse and longitudinal sections of the thallus of an 

 alga may be treated in the same way, but they may be 

 mounted without staining, as the tissues are coloured 

 naturally brown and yellow. 



Ovaries of Flowers. Make transverse sections, which 

 should be as thin as possible, and stain them either in 

 borax carmine or haematoxylin, then clear in clove-oil, and 

 mount in Canada balsam. 



Anthers must be infiltrated with celloidin to keep the 

 pollen in position. Then embed in carrot, place in micro- 

 tome, and cut transverse sections. Stain in borax carmine, 

 and after having passed through acidulated spirit, wash 

 well in methylated spirit, and dehydrate for about one to 

 two minutes in absolute alcohol; then clear in oil of 

 origanum or bergamot, and mount in Canada balsam. 



Flower Buds. Infiltrate with celloidin as directed in 

 Lesson No. II. on Section Cutting. Embed the specimen in 

 carrot, and place in the microtome. Cut transverse sections, 

 stain in borax carmine, and pass through acidulated spirit 

 to remove excess of colour ; if desired they may be soaked 

 until the stain is removed from everything except the 

 nuclei. Wash well in methylated spirit, and place in 

 absolute alcohol for from one to two minutes ; then clear 

 in oil of origanum or bergamot, and mount in Canada 

 balsam. Great care must be taken that the sections do 

 not remain too long in absolute alcohol ; if they should, 

 the celloidin will dissolve, and the sections will fall to 

 pieces. 



Pollens. Place some mature anthers in a large pill-box, 

 and allow them to become perfectly dry. Shake the box 

 well until all the pollen is set free ; then remove the anther 



