Another implement of the chase known as the "Ortner" net is used pretty extensively on the Continent. English entomologists who have used it speak of it most favourably. Its great advantage over other nets is found in the simple and rapid method of its adjustment for use. In connection with nets it may be well to advise the wielder to remember that carrying a threaded needle is a useful practice. Tears and rents are apt to occur, and it is well to have the means of repair handy. [Sidenote: Killing.] Some collectors seem to be expert at killing butterflies by pressing the sides of the thorax together. The method is not, however, as satisfactory as one could wish, and so no more need be said about it. For the happy despatch of insects, the cyanide bottle is frequently used. All that has to be done is to clap the open bottle over the captive while still in the net, then draw the gauze or what-not over the mouth of the bottle until the bung can be inserted, and the whole affair withdrawn from the net. Cyanide of potassium is a deadly poison, and no inexperienced person should attempt to charge a cyanide bottle himself. In fact, chemists are not permitted to supply the poison to unknown customers. Under certain conditions, however, a chemist might consent to make up a killing bottle, and the following instructions may help him in doing this. A fairly strong, clear glass bottle, holding about 4 to 6 ounces; the mouth must be pretty wide, and closed with a well-fitting bung that has been dipped in melted wax; if the bung is of fine grained cork, the wax will not be needed. At the bottom of the bottle place a thick layer of the cyanide, and over this pour plaster of Paris which has been mixed with water and converted into a cream-like paste: one-third of the depth of the bottle to be occupied by the poison and plaster, but only a thin layer of the latter should cover the former. Dealers who supply cyanide bottles (uncharged) also have in stock a brass bottle for chloroform, which some people prefer as a killing agent because it does not change the colour of insects as cyanide is occasionally apt to do. In using this, the insect should be boxed, then a drop of the chloroform may be allowed to run from the bottle over the perforated lid or bottom of the box, and a finger put over the hole or holes for a short time.