SCIENCE-GOSSIP. 



101 



taken to keep each species separate and have the 

 paper cones fastened in such a way that the seed 

 cannot escape. The paper cone should be made 

 large enough to allow the point to be turned down 

 over the heads of the flowers, which will be found 

 sufficient to prevent any seed getting out as it is 

 being expelled from the capsules. In a week or 

 ten days it will be found all the capsules have 

 parted with their seeds, which may now be put in 

 boxes and left to dry still further. 



The reason why boxes are preferred for drying 

 purposes instead of paper is to provide against 

 unlooked-for accidents. I remember once having 

 gathered some capsules of the grass-of-Parnassus 

 (Parnassia palustris) and put them by in paper to dry 

 in my office. A few days afterwards I went to 

 examine them, but the seeds had all disappeared, 

 nothing being left except the gnawed ends of paper. 

 Either mice or cockroaches had been making a 

 repast off them ; but, strange to say, they were the 

 only seeds of several kinds which were touched. 

 All seeds must be thoroughly dried before they are 

 mounted, otherwise they will be attacked by fungi 

 and either damaged or destroyed. A dry, open, 

 airy situation anywhere near a fireplace or stove 

 will be found most suitable. The length of time 

 required for drying will greatly depend on the 

 situation in which they are placed, but under the 

 best of circumstances they should get at least a 

 month. I generally gather in summer and autumn 

 and mount during the winter. 



At first I considered various methods of mounting, 

 but finally came to the conclusion that opal glass 

 slips with vulcanite or brass rings would be the 

 simplest, cheapest, and most effective. The opal 

 slips may be obtained from any glazier, who will 

 be glad to cut them from scraps for a very nominal 

 sum. Their edges may be ground, either on the 

 flat side of a grindstone, using water to prevent 

 chipping, or on a sheet of emery cloth fixed on a 

 piece of wood with tacks, and using oil for grinding. 

 The grinding is a very easy process, all that is 

 required being simply to take off the sharp corners. 

 The opal glass saves all trouble as to forming a 

 background, and the fine enamel or polish of its 

 surface reflects the light and gives an excellent all- 

 round view of the seeds. I do not know whether 

 anyone else has used opal glass for this purpose or 

 not, but its advantages seem to me to be sufficient 

 to recommend to anyone who may wish to make 

 a collection of seeds for the microscope. 



For forming cells, the ordinary vulcanite or brass 

 rings sold by opticians suit admirably ; those half 

 an inch in diameter make the neatest cell, and are 

 quite large enough for ordinary purposes. Smaller 

 rings would not do so well, especially if the cells 

 have to be deep, as it is more difficult with an 

 ordinary bull's-eye condenser to get the light 

 thrown into them. 



For fixing the rings to the slips, and also putting 

 on the cover-glasses, readers will find that one 

 part of gum damar, one part of Canada-balsam, 

 and one part of the ordinary white zinc cement 

 sold for microscopical purposes, will make a most 

 efficient cement for the purpose, using either 

 benzol or benzine as the solvent. For placing the 

 ring on the centre of the slip, a wooden slip may 

 be used, with a hole cut in the centre just large 

 enough to allow the ring to pass through. This 

 will be found very handy and expeditious, and 

 save much time. Put a layer of the cement on 

 one side of the ring and drop it through the hole in 

 the wooden slip with a pair of forceps, on to the 

 glass slip underneath, at the same time pressing 

 the ring hard down. Carefully remove the 

 wooden slip and set the prepared one aside to dry. 

 As soon as the cement is hard enough remove all 

 superfluous cement from inside the cell with the 

 point of a knife and again set it aside for a few 

 days more, so as to make certain the cement will 

 be thoroughly hard before the seed is placed in the 

 cell. A number of slips may thus be prepared at 

 a time. 



Everything being now ready to commence 

 mounting, take one of the boxes containing dried 

 seeds and, if they be large enough, pick them out 

 singly with a pair of forceps and drop them into 

 the cell. When as many seeds as may be required 

 have been, put in the cell, they should all be 

 gathered to the centre, leaving a little margin all 

 round between them and the ring. Do not heap 

 them up. As many as can lie flat in the centre of 

 the cell will be quite enough. Next put on a layer 

 of cement on the top of the ring, taking care not to 

 touch the seeds with it, and then the cover-glass 

 may be dropped on in the usual way, slightly 

 pressing it down in the cement, but not too much 

 so as to cause the cement to run inside the cell. I 

 generally wait for a few minutes after the cement 

 is put on before placing the cover-glass. The 

 cement scon becomes "tacky" and is not so apt 

 to get inside ; but when this is done the operator 

 should provide against dust getting into the cell. 

 In many cases it will be found the seeds can only 

 be cleaned frcm foreign matter by using a lens. 

 In such cases the seeds should be laid on a sheet 

 of white paper, and as many as required separated 

 out with a needle or other suitable instrument. 



After the cover-glass has been cemented on, the 

 slide should be put carefully aside for a week or 

 ten days so as to allow the cement to set thoroughly, 

 care being taken, when moving the slide, not to 

 disturb the seeds and cause them to leave the 

 centre of the cell, which they are apt to do, and 

 become attached to the soft cement. When sure 

 that there is no fear of the seeds adhering to the 

 cement, the slide may be put on the turntable, and 

 a layer of ordinary white zinc cement added, and in 



