152 



THE AMERICAN MONTHLY 



[August, 



Some ten or more years ago, I de- 

 scribed, in Science Gossip, a modifica- 

 tion of Dr. Beale's plan. It was some- 

 what as follows : Take a brass plate 

 3 in. X I in., and ^ an inch in thick- 

 ness, place it carefully on the turntable, 

 and with a "broach," or angle of a 

 broken triangular file, make a circle 

 of the diameter required, then drill it 

 out and remove the burr; heat the 

 brass slide and smear the margin of 

 the aperture with shellac; place the 

 thin glass circle in position, the diame- 

 ter of which need not exceed that of the 

 perforation by more than yi of an 

 inch ; when cold, place the brass slide 

 on the turn-table, and with a writing 

 diamond inscribe a circle on the thin 

 glass of the same diameter as the hole; 

 make some scratches upon it, give a 

 few taps with a file or pen-holder and 

 the central portion of the disk will 

 come away, leaving a cell with clean 

 edges. Heat the brass slide hot enough 

 to readily detach the cell; while the 

 brass is still hot smear again with lac, 

 and cement another disk to it. With 

 ten or a dozen brass plates over a 

 hundred cells can be made in two 

 hours. 



The cells are easily freed from the 

 lac by placing them in alcohol. 

 An ordinary glass slide may be perfo- 

 rated in a similar way. Place it on 

 the turn-table, make a circle upon it 

 with a cutting diamond, cement it 

 (with lac) at right angles to the brass 

 plate, and after scratching or cutting 

 the centre with the diamond, the cen- 

 tral portion may be knocked out with 

 a file, or better still, with a little steel 

 pointed hammer. Perforated slides 

 are useful for mounting foraminifera, 

 small insects, etc., a glass cover at- 

 tached to the slide with shellac or 

 marine glue forming the bottom of 

 the cell, another forming the top, the 

 upper and under surfaces being 

 equally available for inspection. For 

 dry-mounting of diatoms, and objects 

 not much exceeding -^ of an inch in 

 thickness, I have for the last twelve 

 months, been using cells prepared in 

 the following manner: Wash some 



whitening in water to get rid of the 

 coarser parts (foraminifera, sponge- 

 spicules, etc.), or levigated chalk as 

 sold by druggists can be used, and 

 make a mixture about the consistency 

 of cream with weak gum water; three 

 or more applications will make cells 

 of a sufficient depth; when dry go over 

 them two or three times with a solu- 

 tion of Canada balsam dissolved in 

 benzine; the cells should not be used 

 until the balsam is quite hard; then 

 place the cover (upon which the dia- 

 toms ought to be mounted) in posi- 

 tion, and with a heated slide press it 

 upon the cell, when perfectly attach- 

 ed the cement ring can be made in 

 the usual manner. 



Fred. KitTON, 

 Norwich, Eng. Hon'y f. r. m. s. 



Sphagnum^ Desmids^ Bhizopods 

 and Eels. 



A recent visit to a pond in the 

 southern part of New Jersey, prima- 

 rily in search of rhizopods, proved 

 so successful in other respects that it 

 seems worthy of note. Attached to 

 sticks, and floating objects in the 

 water, were great clusters of the beau- 

 tiful alga Batrachospermum monilifor- 

 me, and an abundance of Chantransia 

 jnacrospora in every direction, even 

 growing luxuriantly upon the thallus 

 of Batrachospertnutn. But it was the 

 bog-moss {Sphagfium) that contained 

 the greater variety of microscopical 

 treasures. Following Dr. Leidy's di- 

 rections for collecting rhizopods, the 

 water was squeezed from the sub- 

 merged moss, the result showing 

 what an abundance of living crea- 

 tures a handful cf sphagnum may 

 yield to those interested in micro- 

 scopical studies. Among the rhizo- 

 pods, the most notable forms were 

 Difflugia spiralis, Placocista spinosa, 

 Heleopera petricola, Hyalosphenia 

 papilio, Sphe7ioderia lenta, Nebela cau- 

 data, Nebela ansata, while among the 

 algae, the desmids were present in 

 profusion. The following is but a 

 partial list : Cosmarium cucumis, C. 



