INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 



333 



Deby's Growing- Slide.* — Tliis slide is shown at Fig. 23, in longi- 

 tudinal section. A is a 3 x 1 glass slip, having a glass ring cemented 

 to it so as to form a cell of about ^ inch deep and f inch diameter. 



Fig. 23. 



s 





3 



A small hole is bored through the slip at a, inside and near the edge 

 of the cell. The objects, such as bacteria, &c., are placed with a very- 

 minute drop of water on a thin glass cover B, which is attached to the 

 top of the cell by a little lard. The slip is then laid upon another of 

 the same size but not perforated, and a couple of indiarubber bands h 

 are passed over the ends. One end of this arrangement is then jjlaced 

 in a little water, which, by capillary attraction, will occupy the space 

 between the two slips, and by evajioration will rise into the cell, and 

 prevent the minute drop of water on the glass cover from drying up. 

 By this contrivance a drop of water no larger than a pin's head can be 

 retained of nearly the same size for weeks together, and the develop- 

 ment of bacteria or other minute organisms kept constantly under 

 observation. 



Dunning's Turntable. — Mr. C. G. Dunning suggests a form of 

 turntable to enable the operator readily to centre any slide for 

 moimting up to 2 inches in width, and also to apply the finishing 

 varnish, or repair the same where necessary, to slides, the covering 

 glasses of which may have been placed away from the centre in either 

 direction. The apparatus, which is shown in Fig. 24 (half size), 



Fig. 24. 



consists of tlic usual circular tal)h', witli tlio addition of a dovetail 

 groove across the centre, in which work tlie guides of two clips. One 

 of these clips is fixed to its guide, and the other works on a pivot in 

 order tliat it may adjust itself to any little irregularity in the width 

 • '.Tnuni. f^tick. I\Iirr. ('liil>," v. (1880) p. 2S, 



