928 SUMMARY OF CURRENT RESEARCHES RELATING TO 



to write upon ttan if already cut up, and having a definite space 

 between each the sheet is readily cut up, no trimming being required. 

 The use of square pieces of card of varying thickness, placed 

 under the labels, forms a valuable protection to the object mounted 

 between, further allowing of the slides being packed together side by 

 side, thus obviating the necessity of rackwork during transit. 



Examining Sponges.* — H. J. Carter considers that the " quickest 

 way to examine a sponge is to soak a microscopic fragment of it in 

 distilled water for from twelve to twenty-four hours ; then tear it to 

 pieces on a slide, drain, dry, and mount with balsam as usual ; but to 

 be certain of the exact form of its spicules requires that they should 

 be boiled out with nitric acid, which may also be easily and quickly 

 eflfected by placing the microscopic fragment on the centre of a glass 

 slide and covering it with a drop or two of nitric acid, then boiling 

 this over a spirit-lamp with low flame till it is nearly dry, after which 

 the same process must be repeated twice or thrice ; and, finally, before 

 the last drop of nitric acid is entirely dried up, removing the slide to 

 the table, when, through gradually increased inclination and sufficient 

 but careful edulcoration with distilled water, the residuum may be 

 freed from all remaining acid, drained, dried, and mounted in balsam ; 

 or, if desired, another microscopic fragment, prepared as first men- 

 tioned, may be added to it previously, when the perfect form of the 

 spicules respectively, together with their position in situ, may be seen 

 at once in the same preparation." 



Exhibiting Volvox and Amoeba.f — Part of Mr. J. Levick's 

 Presidential Address to the Birmingham Natural History and Micro- 

 scopical Society is occupied with the methods of "displaying" 

 microscopic life, more es^Decially Volvox globator and Amoeba, which 

 he describes as follows : — 



" I directed my first attention to what may be called massing or 

 crowding them together, getting them out of dirty into clean water, 

 freeing them from other things which it was undesirable to show at 

 the same time, and several methods succeeded very well. 



Let us suppose that we have a jar with a good gathering of 

 Volvox, and we wish to get them so thickly together that the whole 

 field of the Microscope may be filled with them, nothing being more 

 beautiful as an object of display. The most natural way to attain this 

 is by filtering them out, and for this purpose I have made some small 

 metallic sieves, the mesh of which is not more than 1-1 00th of an inch 

 in breadth, such as the one I now have before me. This I place in a 

 small shallow vessel, pouring the water not through, but outside the 

 sieve, and then by means of a small syringe withdraw the water 

 through this fine gauze, continuing the process until I get the Volvox 

 at the bottom of the earthenware vessel as thickly together as I like. 

 They may then be picked up by means of the syringe, and placed in 

 any quantity or density upon a slide or compressor, care being taken 



• Ann. and Mag. Nat. Hist., xii. (1883) p. 317. 



t Report ami Trans. Birmingham Nat. Hist, and Micr. Soc. for 1882, pp. 

 xvii.-xxiii. 



