92 



THE AMERICAN MONTHLY 



[May, 



by many others. We refer to the 

 process of mounting in cells made of 

 wax. Many writers have condemned 

 the method, on the ground that in 

 time a peculiar deposit forms on the 

 lower side of the cover-glass in all 

 wax cells. Such a deposit has not 

 been observed by the writer, and as 

 statistics may be regarded as of value 

 in this connection it may be said that 

 in the year 1S77 we prepared a large 

 number of slides of foraminifera in 

 wax cells. Opening a drawer in the 

 cabinet this morning we found twenty- 

 five of those cells, and the covers of 

 all are as clear as when they were 

 put up. With such experience we 

 do not hesitate to recommend the 

 use of wax cells, but owing to the 

 numerous complaints from others we 

 would advise those who do use them 

 to follow strictly the methods that 

 have proved successful in our hands.* 



AIo7inting in Wax Cells, — Unfor- 

 tunately black w^ax cannot be obtain- 

 ed, but the darkest olive-green vs^ax 

 in sheets, as sold for making wax 

 flowers, is a good substitute, and has 

 been exclusively used by us. The 

 entire cell may be made of wax, but v\^e 

 generally prefer to use curtain-rings 

 for the sides and wax for the bottom. 

 In making the entire cell of wax the 

 method is to put a sufficient number 

 of sheets together to make the re- 

 quired thickness, cut out a square, or 

 punch out a round piece of proper 

 size, place it on a slide on the turn- 

 table, pressing it down to make it ad- 

 here, and then turn out the cell with 

 a pen-knife. The details of this 

 method have been given in back num- 

 bers of this Journal. t 



To make the cells with curtain- 

 rings proceed as follows : Select the 

 ring to be used, a ^-inch or |^, ac- 



*Dr. E. Weissflog is of the opinion that 

 the spoiling of preparations is partly due 

 to the cover-glass itself, which has been 

 observed to become covered with mois- 

 ture[?] on the surface when packed away, 

 or perhaps decomposed on the surface. 

 See vol. ii, p. 49. 



fVol. i, pp. 46 and 150. 



cording to the object, and punch out 

 a single thickness of wax as large or 

 a trifle larger than the outside diame- 

 ter of the ring, for which purpose a 

 gun-wad punch will be found very 

 useful. Place the wax upon a slide, 

 centre it on the turn-table, lay the 

 curtain-ring upon it and centre that. 

 Then hold the slide over a lamp un- 

 til the wax softens, but do not let it 

 melt or the finish of the surface will 

 be spoiled. The ring thus becomes 

 embedded in the wax, and if it should 

 be slightly decentered by the opera- 

 tion the slide may be returned to the 

 turn-table while still warm and the 

 error corrected. 



As soon as the v^^ax cools the ring 

 v^ill be found firmly attached to the 

 slide, the bottom of the cell will be 

 clean and smooth, quite ready to re- 

 ceive any object. 



The object may now be placed in 

 the cell and caused to adhere by 

 means of gum water or by soften- 

 ing the surface of the wax with spirits 

 of turpentine on a brush. When the 

 turpentine evaporates the objects will 

 be found securely attached, and the 

 cover-glass may be applied. 



To cement the cover-glass we are 

 accustomed to use clear shellac in al- 

 cohol, as described last month. The 

 cover being securely cemented down 

 the next operation is to finish the out- 

 side of the cells, so as to give them a 

 neat appearance. This may be done 

 in white, black, or in various colors, 

 but as a rule the neatest mounts are 

 the plainest. 



A white finish ma}' be given with 

 white zinc cement, which is a good 

 material for finishing slides, but not 

 reliable as a cement for making cells 

 and holding covers, as it is liable to 

 run in after a time. Perhaps it is 

 possible, by extreme care in drj^ing 

 the cement, to avoid running in, 

 since it is true many good mounters 

 use it, but we are writing from a tol- 

 erably extended experience, and the 

 presumption is that this experience is 

 a reasonably good indication of what 

 others will have, who are no better or 



