354 



TECHNOLOGY OF DIATOMS. 



Cells. — When large Diatoms are to be mounted separately, 

 especially those with long, fragile appendages, the use of a cell 

 becomes a necessity. The most simple method is this : — You 

 prepare a solution of gum arable as thick and as pure as possible. 

 The water employed to dissolve the gum should previously be 

 deeply coloured with some aniline dye ; then, by means of a 

 turn-table, you make on the centre of the cover-glasses already 

 cemented a little cell from i to li mm. interior diameter, and 

 about i/io mm. thick, and leave it to dry perfectly. The other 

 kinds of cells are less useful and more difficult to make, requiring 

 the use of costly instruments. 



Artistic and Systematic Preparations. 



These preparations, which certainly are very beautiful when well 



done, call for much skill on the part of the operator. The use of 



a movable stage then becomes indis- 

 pensable. To enable you to place 

 the objects regularly at equal dis- 

 tances at right angles or in curves, 

 you use glasses divided into i/io 

 mm., which are placed in the eye- 

 piece (Figs. 2 2 and 23). Fig. 23 helps 



to make those pretty rosettes, which certainly the greater part of 



our readers have admired. 



We beg to thank Mons. J. Tempere for the use of the blocks 



by which this and the previous paper are illustrated. — Ed. 



Fig. 22. 



Fi.£?- 23. 



Distribution of Fungi by Snails and Toads.— Voglino 

 communicates a suggestive paper to the Nuovo Giornale Bot. Ital. 

 (1895, 181), in which he demonstrates that certain fungi {Agari- 

 cinice) are distributed by snails and toad.s. An examination of the 

 stomachs of the snails showed the presence of the spores of 

 various species of fungi which were seen to have begun their ger- 

 mination, and culture experiments with the excrements of various 

 snails produced a large number of germinating spores of fungi. 

 The same was observed on examining the stomachs of toads, in 

 which the spores of Russula and Lactariiis were specially abun- 

 dant. — Pharmaceutical Jourtial. 



