ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 843 



of the trouble and time expended in making these solutions, now adopted 

 the following method. 



The preparation is placed on a slide with a drop of zinc chloride solu- 

 tion ; to this is added a drop of a weak iodine solution, and the cover-glass 

 is then imposed. The reaction immediately takes place, and if the chloride 

 is in excess, the iodine colour disappears from everywhere except the stained 

 parts of the preparation. It seems indifiereut which reagent is first used. 



Mounting Mosses.* — Miss V. A. Latham gives the following directions 



for mounting mosses : — 



" We will take the pretty moss, Dicranum lieteromaUns. The chief 

 beauty in this moss lies in the capsule, and I may remark here that mosses 

 for mounting should be in fruit, and, what is more, ripe. The peristome 

 is very pretty, and we must try and preserve the capsule uninjured. In its 

 natural state, when growing and quite ripe, the calyptra and operculum are 

 thrown off, the peristome unfolds itself, and the spores issue from the capsule, 

 and either fall to the ground or are scattered by the wind. All this should 

 be borne in mind whilst mounting mosses, and if you can show the spores 

 leaving the capsule, and also the calyptra and operculum, so much the 

 better. Gently shake, and remove, with the aid of a small sable brush, as 

 much dirt, dust, and grit as you can. Then place the specimens ia clean 

 water, and shortly the leaves will expand and look as fresh and green as 

 when growing. Use your brush, and move them carefully and quickly 

 about in the water to further cleanse them. Transfer to a small bottle of 

 water again, and shake carefully. Change the water, and repeat if necessary. 

 During washing the opercula will probably fall from the capsules ; there- 

 fore keep a look out. Take from bottle, examine your specimens, and 

 remove ragged and imperfect portions, if any ; place upon slip, and see if 

 clean with a low power. If so, you will be lucky. Most probably you will 

 find it necessary to use the brush again, holding the moss under water with 

 one brush whilst you clean with another. You can try placing them in a 

 saucer, and letting the water tap drop on them. Now arrange your moss 

 on a slip, unfold and spread out the leaves gi'acefully and naturally, and 

 with the capsules placed with an eye to artistic effect, as if growing. Put 

 three small beads or portions of broken glass circles for the edges of your 

 cover-glass to rest evenly upon, so as not to rest upon and burst the cap- 

 sules, and to prevent tilting. Put on the cover-glass and secure witli wire 

 clip ; drop the glycerin jelly round the edge of the cover, and it will run 

 under. Now gently heat until ebullition takes place. This operation 

 requires a little practice, but when done successfully, it drives out all aii'- 

 bubbles, liberates a few spores from the capsule, and makes the leaves more 

 transparent for examination Should the spores leave the capsule in excess 

 and cloud the field, transfer to clean slip and repeat the process. Good 

 glycerin jelly will sut immediately, when you may possibly find the boiling 

 bas interfered a little with the nice (that is, natural) position of some of 

 the leaves and capsules. If so, warm the slide until the jelly is in a fluid 

 state, insert the needle under the cover, and replace all straight ; at the 

 sam« time, and by the same means, push under and place in position the 

 opercula. 



Occasionally there may be a desire to preserve intact the beautiful 

 fresh green tint of the leaves. In that case, after you have got your 

 moss clean, soak it in glycerin for several weeks until the glycerin has 

 thoroughly permeated and driven out all air from the capsules and leaves. 

 When ready, place a warm slip on your mounting stage, put your moss in 



* Sclcntif. Enquirer, ii. (1887) pp. 156-7. 



