MICROSCOPIC OBJECTS. 163 



variety of diverting pranks and tricks ; some engaged in a 

 fierce and obstinate combat ; others darting between the 

 branches in search of prey ; and others cautiously avoiding 

 the more predacious ones. 



(13.) Another plan is to confine the insects as shown 

 in the following figure, which represents a plate of glass 

 covered by one of metal of suitable thickness cemented 

 to it, and having an aperture in the latter to receive the 

 insect, which is covered by a plate of thin glass. This 

 plan is valuable for viewhig the circulation in plants 

 under a vertical microscope. 



(14.) Aquatic Live Boxes. — ^The most useful of all 

 these contrivances is the aquatic box represented in figure 

 21 of the ' Microscopic Illustrations.' It consists of a 

 short piece of tube, the lower end of which is fitted to 

 the stage of the microscope, or fits into the slider-holder, 

 having a circidar piece of glass fixed to its upper 

 end; over this fits another piece of tube forming the 

 cover, with a circular plate of thin glass fixed to it, the 

 objects being situated between the box and the cover. 

 They may be made of various sizes, and by sliding the 

 cover more or less on the box, the distance is varied to 



Q 



