2074 Journal of Applied Microscopy 



The psychological influence of a beautiful building is not to be lightly con- 

 sidered. Museum curators are themselves at times too indifferent to these 

 influences, and, immersed in the scientific interest or rarity of collections of 

 specimens, fail to realize how the receptivity of the common public is stimula- 

 ted by environmental charm. 



The architectural marking of the box can be effected in three ways : (1 ) By 

 the successional relief of the facade by towers, columns, square or round, as 

 unity of design requires ; (2) by surrounding the box by colonnades, or so com- 

 bining the box units as to form irregular re-entering or projecting surfaces ; or 

 (3) by simple embellishment. 



The first device is exemplified in the Kensington Museum, the American 

 Museum of Natural History (Fig. 4), the Provincial Museum, Hanover (Fig. 5), 

 the Vienna Hof. Museum, etc. ; the second, in the National Library, Dublin, the 

 National Museum, Washington, in a measure in the Art Museum of New York, 

 etc. ; the third (combined with the first), in the Corporation Museum and Art 

 Gallery of Glasgow, and also in the Art Museum of New York (Fig. 6). 

 American Museum of Natural History. L. P. GratacAP. 



Sectioning Fresh Plant Tissues. 



In histological studies of leaves and other thin plant tissues, it is often very 

 desirable to make sections, serial or otherwise, which have never been injured 

 through chemical processes of hardening and embedding nor by the heat to which 

 the tissues are exposed in paraffin embedding. Free hand work is often satis- 

 factory, but by this method the sections of a series are apt to vary greatly both 

 in thickness and in the angles at which they are cut. Where greater uniformity 

 is desired, the writer has practiced a system of rapid and efficient embedding 

 which may prove useful to other workers. 



For embedding a small piece of leaf or other like tissue, two pieces of paraf- 

 fin are used, each piece being about 20 mm. long, 14 mm. wide, and 3 mm. 

 thick. The portion of leaf to be embedded is properly placed near the center 

 on one piece of parafiin and the other piece is firmly pressed above it in 

 such a manner that the margins of the two pieces of parafiin coincide and are 

 pressed firmly together. A heated scalpel is now run entirely around the edges 

 of the parafiin blocks so as to firmly melt them together where touched. The 

 entire cake, containing the centrally embedded square of leaf tissue, is then 

 thrown into cold water until sufficiently firm to be fixed upon the microtome 

 plate and trimmed for sectioning in the usual manner. Where paraffin is of the 

 right degree of hardness, is held at the proper temperature, and the other con- 

 ditions are as they should be in all microtome work, it is not difiicult to 

 obtain uniform sections of five microns thickness and of perfectly fresh plant 

 tissues. 



I usually keep a box filled with suitable parafiin pieces, so that a number of 

 squares of leaf tissue may be embedded at one time, stiffened in water, placed in 

 the microtome, and sectioned in a fresh and uninjured state in a few minutes 



