1038 RECORD OF CURRENT RESEARCHES RELATING TO 



itself is quite efficient as a preservative. It therefore occurred to him 

 to combine them, two parts of salicylic acid and one part of borax 

 dissolving completely in half an ounce of glycerine — this solution, 

 when mixed with three parts of water, forming an excellent preserva- 

 tive fluid for coarse organisms. More delicate preparations should be 

 mounted in the above solution diluted with five parts of water. 



Preparations so mounted are very durable, and there is no danger 

 of the salts crystallizing out and spoiling the object, and, in addition, 

 it is very easily kept in a cell of almost any kind. 



Dry "Mounts" for the Microscope.* — Prof. Hamilton L. Smith, 

 referring to his former papei',f in which he described the methods 

 which he had found tolerably successful, viz. the rings made of shellac 

 and lampblack, and those punched out of gutta-percha tissue, further 

 says "that the former appear to answer quite well, and the changes if 

 any are very slight, yet he has in a very few cases observed a 

 deterioration after the lapse of a year or so, probably from imperfect 

 manipulation. Although he has not observed any great change in 

 the gutta-percha mounts, he is not certain they will stand prolonged 

 use with immersion objectives without injury. Messrs. Spencer are 

 decidedly of opinion that the shellac ring is the better for durability ; 

 and Mr. Gundlach says that the gutta-percha ring will not stand cedar 

 oil. Dr. Phin has suggested that in time the gutta-percha tissue will 

 disintegrate, but the author has not yet noticed this, and does not 

 think it will happen under the cover of a " mount," especially if pro- 

 tected by a ring of cement subsequently applied. If it does, it will 

 of course be a great objection to its use. The " tissue " becomes so 

 charged with electricity by handling, and also by punching, that it 

 interferes seriously with the latter operation, and thus makes it neces- 

 sary to place strips of the " tissue " on thin moistened strips of paper, 

 and to punch out both at the same time. The preparation of the 

 shellac rings by the turntable obliges one to keep on hand a large 

 stock all the time, to ensure perfect drying and to have them always 

 ready. The author is obliged to have some 1000 or 1500 on hand in 

 advance, and this necessitates a considerable outlay in stock which 

 will not always be convenient for amateurs. 



For the above reasons, a new process is now proposed which 

 appears to meet all the desired wants, and which combines the 

 advantages of the shellac cement and the gutta-percha rings. The 

 author says that " the very simplicity of this process causes him to 

 wonder why it was not thought of before." 



Take a sheet of thin writing paper, white or coloured, and dip it 

 into thick shellac varnish (shellac dissolved in alcohol), and hang it 

 up to dry. When thoroughly dry, it should have a good glaze of 

 the varnish on it (different thicknesses of paper can be used according 

 to depth of cell required). Out of this shellac paper cut the rings, 

 and these can be made in any quantity, and kept for any time. The 

 process of mounting is simple. The slide is cleaned and the flat 

 paper ring placed in the centre ; on this the cover is placed, having 



* ' Science,' i. (1880) p. 74. t See tliis Journal, ante, p. 861. 



