82 THE MICROSCOPIST. 



The net should be confined by an india-rubber band in a 

 groove, so as to be slipped off readily and emptied into a 

 bottle. The collector should have enough bottles to keep 

 organisms from each locality separate, and when animal- 

 cules are secured enough, air should be left to insure their 

 safety. 



Marine organisms may be obtained in a similar way if 

 they inhabit the neighborhood of the shore, but others 

 can only be secured by means of the dredge or tow-net. 

 The latter may be of fine muslin sewn to a wire ring of 

 twelve inches diameter. It may be fastened with strings 

 to the stern of a boat, or held by a stick so as to project 

 from the side. For the more delicate organisms, the boat 

 should be rowed slowly, so that the net may move gently 

 through the water. Firmer structures may be obtained 

 by attaching a wide-mouthed bottle to the end of a net 

 made conical, and double, so that the inner cone may act 

 as a valve. The bottle may be kept from sinking by a 

 piece of cork. Such a net may be fixed to the stern of a 

 vessel, and drawn up from time to time for examination. 



Minute organisms may be examined on the spot by 

 fishing them out of the bottle with a pipette, or small 

 glass tube, and placing them on a slide. A Coddington 

 or other pocket lens will suffice to show which are desir- 

 able for preservation. 



Many of the lower animals and plants may be kept 

 alive in glass jars for some time. Frogs, etc., may be 

 kept under wire covers with a large piece of moist sponge. 



Aquaria of various sorts may be procured and stocked 

 at small expense, and will afford a constant source of in- 

 struction. For fresh-water aquaria the bottom of the jar, 

 etc , should be covered with rich black earth, made into 

 a paste, and this should be surmounted with a layer of 

 fine washed sand. Roots of Valisneria, Anacharis, or 

 Ckara may then be planted in the earth and the vessel 

 filled with water. As soon as the water is clear, put a 



