Preparation and Mounting of Vegetable Tissues. 91 

 green, and after washing in water mount in glycerine 



jelly. 



Scalariform Vessels. Treat pieces of the rhizome of 

 Pteris aquilina in exactly the same way as stem of maize. 



Spiral Vessels. Treat pieces of the stem of rhubarb as 

 above. 



Yeast. Get some fresh baker's yeast, place a little of it 

 in a bottle of sugar and water, and stand in a warm place 

 for twenty-four hours. Pour off the sugar water and 

 add camphor water. Make a cell on a slide with black 

 shellac cement, and let it dry ; then apply a second coat of 

 cement, and let this stand for a few minutes. Now take up 

 some of the yeast in a glass tube and place a few drops in 

 the cell ; clean a cover-glass, and bring its edge in contact 

 with the cement on one side of the cell ; ease it down 

 carefully, so that no air-bubbles may be enclosed ; now 

 press on the surface of the cover with a needle until it 

 adheres firmly to the cell all round, drain off the excess of 

 fluid, dry the slide with a clean cloth, and apply a coat of 

 cement. 



Preserving Fluid for Green Algae. Acetate of copper, 

 15 grains ; camphor water, 8 ounces ; glacial acetic acid, 

 20 drops ; glycerine, 8 ounces ; corrosive sublimate, 1 grain. 

 Mix well together, filter, and keep in a stoppered bottle. 

 The above fluid preserves the colour of chlorophyll for a 

 long time ; it may also be used as a mounting fluid. For 

 very delicate specimens leave out the glycerine. 



The specimens should be well washed in water ; then 

 pour off the water, and add a quantity of the copper 

 solution. 



To Mount in the above. For example, take spirogyra 

 as a filamentous alga. Make a cell with some black 

 cement, and let it dry ; then apply a second coat of cement, 

 and allow this to nearly dry, Place some spirogyra in the 

 cell, and with needles separate the filaments ; add a few 

 drops of copper solution, and apply a cover-glass as directed 

 for yeast. 



