MICROSCOPIC ACCESSORIES. 41 



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most skilled artists who are unfamiliar with microscopic 

 manipulation. 



Other accessory apparatus, such as a frog-plate, for more 

 readily observing the circulation in a frog's foot ; an 

 animalcule cage, or live box ; a compressor ium, for apply- 

 ing pressure to an object ; fishing tubes ; watch-glasses ; 

 growing-slides, etc., will commend themselves on personal 

 inspection. 



For preventing the evaporation of fluids during obser- 

 vation, Recklinghausen invented the moist chamber (Fig. 

 20), consisting of a glass ring on a slide,. to which is fas- 

 tened a tube of thin rubber, the upper end of which is 

 fastened round the microscope tube with a rubber band. 



FIG. 20. 



Keckliugliausei.'s M..ist i liambor. 



A simpler form of moist, chamber may be made by a 

 glass ring cemented on a slide. A few drops of water 

 cautiously put on the inner edge of the ring with a brush, 

 or a little moist blotting-paper may be placed inside. The 

 object (as a drop of frog's blood, etc.) may then be put on 

 a circular thin cover, which is placed inverted on the ring. 

 A small drop of oil round the edge of the cover keeps it 

 air and water-tight. 



Somewhat similar to the above is Strieker ' gas chamber 

 (Fig. 21). On the object-slide is a ring of glass, or putty, 

 with its thin cover. Through this ring two glass tubes 

 are cemented, one of which is connected with a rubber 



