226 The Microscope. 



fresh-water lobster, the gills and skin of the numerous species of 

 mollusks, the blood and intestinal tract of frogs, newts, snakes, 

 insect larvae, and many other well-known hosts. An examination of 

 the intestines of the earth-worm, the intestines and surface of 

 aquatic worms, and the stomachs of ruminating herbivores will disclose 

 many forms — some among the most remarkable and striking. The 

 minute Crustacea abounding in every collection of fresh-water are 

 favorite hosts of the Infusoria. 



Now that a partial indication of where to look for our objects 

 has been given, let us inquire when may they be found ? Practi- 

 cally, the year round. Of course they are in greater abundance 

 throughout the summer season than in winter, when the ponds and 

 streams are mantled with ice, and the water beneath is at best but 

 little above freezing temperature; still, in mid-winter, when the natu- 

 ralist usually suspends field-work, many species may be taken from 

 under the ice. 



It seems hardly necessary to take much space in describing the 

 apparatus and manner of using it; so, briefly, I have found the 

 following contrivances handy : a minnow-net on a stout pole six or 

 eight feet long— this will bring out of moderately deep water crays, 

 larvae, small fish, weeds, etc. ; a drag, consisting of a lead of five to 

 eight poiuids weight with stout copper- wire hooks— this may be thrown 

 out many feet from shore, or used in deep water for hauling in 

 aquatic plants; a tow-net of silk-mull for skimming the surface; a 

 small water-net for general use in concentrating the catch. The 

 modification that suits me best is the usual conical form made of 

 mull, with a short piece of | or | inch rubber-tubing, kept open at 

 the upper end by a piece of stout glass-tubing bound into the apex 

 of the net ; when in use, the tube may be closed by a cork or have a 

 wide-mouthed tube- vial inserted, the bottom of which has been re- 

 moved and a net of mull tied over it. The usefulness of this vial 

 into which the captured forms soon descend and are so readily re- 

 moved to convenient receptacle, is obvious. Another useful piece is 

 the dipping-bottle; this and the small net may be made to work at 

 the end of a common cane; a longer stick will be found convenient 

 often, but by using a plain walking-stick one avoids the curious and 

 the "crank" who always wants to know how the fish bite, or what 

 you are fishing for, particularly if he sees you about some muddy 

 puddle, how provoking to a sensitive nature! I would advise the 

 collector to use plenty of wide-mouthed bottles for canying what 



