1883-84] Edinburgh Naturalists' Field Club. 151 



VIII.—NOTE ON THE MOUNTING OF MICROSCOPIC OBJECTS 

 IN MONOBROMIDE OF NAPHTHALINE. 



By \V. IVISON MACADAM, F.C.S., F.I.C. 



(Read Feb. 28, 1884.) 



I HAVE thonglit it might be of interest to the members of the Club if 

 I gave a few notes on the method of mounting objects for the micro- 

 scope in the new medium, Monobromide of Naphthaline. The index 

 of refraction of this medium is so different from that of the ordinary 

 Balsam, that the striation of Diatoms is brought out with a clear- 

 ness never before obtained. Weissflog of Dresden, who has employed 

 the medium for over three years, says that in mounting Diatoms he 

 uses only a thick solution of shell-lac, and never wax or gold-size. 

 After making the ring with the shell-lac, a drop of the medium is 

 placed with the Diatoms on the cover, and pi;t in position on the 

 ring. After removing extra liquid with blotting-paper, the edges are 

 coated with thick gum-arabic, and allowed to dry. When quite dry, 

 it should then receive one or two coatings of sealing-wax dissolved 

 in alcohol, and lastly a coat of pure shell-lac. Common glue will be 

 found good for the cell, and the last coat may be one of water-glass. 



The substance is by no means an easy one to work with, and 

 failures may be expected during the early trials. However, the 

 result, as may be obseived from the slides shown, is well worth the 

 trouble and pains necessary. When successfully conducted, the slides 

 remain perfect for a long period, the great point being the careful 

 coating of the edges with the gum-arabic. The Eev. George Davidson 

 of Logie-Coldstone has had slides for over five years, and they are as 

 perfect now as when first obtained. The slides shown, both in balsam 

 and in the new medium, are mounted by that gentleman. 



IX.— THE STRUCTURE AND HABITS OF CARNIVOROUS 

 PLANTS. 



By Mr A. D. RICHARDSON. 



{Read Feb. 28, 1884.) 



To sustain plants in a healthy condition, a supply of nitrogen is 

 essential. Although that element forms nearly four-fifths of the air 

 we breathe, plants have no power of taking it in from the atmosphere 



VOL. I. L 



