The Microscope. 7'.> 



Dry chloride of lime, - - - - 2 oz. 



Soda crystals (washing soda), - - - 3 oz. 



Water, ---... 2 pts. 



Mix the chloride of lime with half the water, and the soda with 

 the other half, — mix the whole togetber, and allow to settle in a well 

 corked bottle. Pour off the clear liquid for use, which should be 

 kept in a bottle with glass stopper. 



Pour the alcohol and water fi'om the fern and supply its place 

 with bleaching fluid, and place in a strong light if you wish to 

 hasten the process. Look at them often, and as fast as the leaves 

 appear to be bleached examine with a lens, and if there is no remain- 

 ing appearance of chlorophyll in the sporangia or in the leaf, the 

 bleaching has gone far enough. It is not always safe to wait for a 

 stout midvein to become perfectly clear, for a very little over bleach- 

 ing may injure or ruin the fern. Some are much harder to bleach 

 than others, and in some cases it may be necessary to change the 

 fluid two or three times. 



When the bleaching is completed — discarding all chemicals rec- 

 ommended for the purpose of removing the chlorine, — remove the 

 leaves to a liberal quantity of soft water, which should be changed 

 once in an hour or two, till there is no trace of chlorine remaining; 

 if the chlorine is not all soaked out the staining will be a failure. 

 Remove finally to alcohol for hardening the tissues, which by this 

 time may have become somawhat soft, where they may remain indef- 

 initely if the alcohol is perfectly clean; if not clean, they will be 

 soon ruined. 



It should be remembered that it is impossible to give exact for 

 mulae for double staining that will work every time, for staining 

 fluids are not all alike, and other conditions may vary, and some- 

 thing after all must be left to the judgment and skill of the manip- 

 ulator; the following, therefore, may be accepted rather as the basis 

 of experiment than as exact rules. 



For showing epidermal structure, use alum carmine and methyl 

 green, in the proportion of one drop of methyl green to ten drops 

 of alum carmine in a watch glass, measured with a dropper for 

 exactness. There is no rule but experience for time required; it 

 may be an hour, or it may be longer, according to the character of 

 the fern or the depth of stain required. Just the right time will 

 stain the spores, and often the spore cases, a beautiful green and 

 the leaf a fine red; sometimes the larger veins also will take the 

 green, and the entire epidermal system will be shown perfectly. If 



