244 



COLLECTION OF OBJECTS. 



which are themselves, on account of their minuteness, essentially 

 microscopic ; and the collection of these requires peculiar methods 

 and implements, which are, however, very simple, — the chief 

 element of success lying in the knowledge where to look, and 

 what to look for. In the present place, general directions only 

 will be given ; the particular details relating to the several groups, 

 being reserved for the account to be hereafter given of each. 



143. All the Microscopic organisms in question, being aquatic, 

 must be sought for in pools, ditches, streams, or other collections 

 of water ; through which some of them freely move, whilst others 

 attach themselves to the stems and leaves of aquatic plants, or 

 even to pieces of stick or decaying leaves, &c., that may be float- 

 ing on the surface or submerged beneath it, while others, again, 

 are to be sought for in the- muddy sediments at the bottom. Of 

 those which have the power of free motion, some keep near the 

 surface, whilst others swim in the deeper waters ; but the situa- 

 tion of many depends entirely upon the light, since they rise to 

 the surface in sunshine, and subside again afterwards. The Col- 

 lector will therefore require a means of obtaining samples of 

 water at diiferent depths, and of drawing to himself portions of 

 the larger bodies to which the microscopic organisms may be 

 attached. For these purposes, nothing is so convenient as a rod 

 about five feet long, which may be divided into two pieces jointed 

 together ; and the farther extremity of this rod should be pierced 

 with a hole, passing for some distance into its length.' Into this 

 hole, as a socket, may be fitted either of the three implements 

 which the Collector may happen to require. If he desires to 

 take up samples of the water, he will need a wide-mouthed bottle, 

 containing about 2 oz. This may be attached to the extremity 

 of the rod, by simply passing round its neck a strap of thin whale- 

 bone or sheet gutta percha, the two ends of which are to be 

 brought together and inserted into the socket, in which they may 

 be secured by a plug of soft wood or cork. The bottle being 

 held sideways with its mouth partly below the water, the surface 

 may be skimmed ; or, if it be desired to bring up a sample of the 

 liquid from below, or to draw into the bottle any bodies that may 

 be loosely attached to the submerged plants, the bottle is to be 

 plunged into the water with its mouth downwards, carried into 

 the situation in which it is desired that it should be filled, and 

 then suddenly turned with its mouth upwards. If, again, the 

 organisms which it may be desired to collect, are of suflicient 

 size to be strained out of the water by a piece of fine muslin, a 

 ring-net should be fitted into the socket of the rod. This may 

 be made by sewing the muslin bag to a ring of stout wire, fur- 

 nished with a projecting stem which may be inserted by means 

 of a cork into the socket of the rod. But it is more convenient 



' Cheap fishing-rods are now sold at the toy shops, which answer this purpose ex- 

 tremely well, the last or slenderest joint being laid on one side; its socket in the last 

 joint but one, being well adapted to receive the littings above described. 



