THE MICROSCOPE AND ITS PARTS. 35 



the microscopist can have on his table, if he intends to 

 study aquatic life. "With it he can pick up any small 

 object that may be visible in the water, transfer any se- 

 lected matters to the slip, or make the dip that is made 

 by faith, with the assurance that although the tube may 

 seem to be filled with water only, it will be pretty sure 

 to have captured something interesting, novel, or beau- 

 tiful. He can fill the tube with water, and allow it to 

 escape in a miniature torrent, or drop by drop, or he 

 can allow a drop to enter and a drop to flow slowly out 

 at his will. Some workers prefer a tube with a hollow 

 rubber bulb attached, by which the water and contained 

 objects are drawn up by the expanding ball, and forced 

 out by its compression. The writer is prejudiced in favor 

 of the simple tube, as it is less complicated, more easily 

 cleansed, and its contents are more completely under 

 control. To use it, place the tip of the forefinger firm- 

 ly over one end, and dip the other into the water above 

 and near to the object desired ; lift up the finger, and the 

 water will rush in until it is level with that on the out- 

 side ; close the upper end again, remove the tube, and 

 the water will remain in it as long as the finger stops 

 the upper opening ; remove the finger and the water 

 will at once flow out. By the proper regulation of the 

 pressure and movements of the finger, the water can be 

 made to escape drop by drop or in a sudden rush. In 

 this way any small aquatic object can be easily trans- 

 ferred to the slip, and as readily washed off by a sudden 

 outward flow from a full tube. 

 3 



