38 THE AMERICAN MONTHLY [Feb., 



be raised rapidly from the water at the side of the boat, 

 and held suspended from its tow-line until it has emptied 

 itself of water, mostly of course by percolation through 

 the lower portion of the cloth ; it is then soused in the 

 water again and lifted as before, and after repeating this 

 procedure three or four times the solid particles have 

 nearly all been washed down into the tube at the bottom 

 and into the adjoining portion of the net. This portion, 

 still held vertically, and with the tube (s) full of water, 

 is then brought over the edge of the boat, and held over 

 one of the wash-bottles while the screw-cap (t) is care- 

 fully removed, and the water with most of the organisms 

 allowed to fall into the bottle. If the collection be small 

 or for other reason it be desirable to save as much mate- 

 rial as possible, the cap is securely screwed on (not 

 dropped overboard), the net soused again, and the wash- 

 ing-out repeated ; and so on until the water comes clear 

 from the net. If, unfortunately, the screw-cap should be 

 lost, one of the muslin filters can, instead, be tied over 

 the end of the tube (s); but it would be inferior in safety, 

 and, as the whole collection will not adhere to this fil- 

 ter, the other procedures would still be necessary and 

 would be performed at a great disadvantage. It is there- 

 fore better, if one fears the loss of the cap, to connect 

 it with its tube (s) by a few inches of strong twine, ar- 

 ranged slack, so that the cap can be unscrewed but cannot 

 be lost. The cap and tube are the common kerosene-can 

 top, to be obtained at any tin-shop. 



Of course the net and screw-cap are thoroughly rinsed 

 before and after each collection, the organisms from 

 marshy shores or weedy beds or streams, where most 

 will be obtained, being kept carefully separate from 

 those of the clear water ; and in the latter case those of 

 the surface and deep water being kept apart, and the 

 hour of day and state of weather being carefully recorded, 

 as essential to an understanding of the distribution and 



