Methods of Preserving Marine Biological Specimens. 527 



tinct. ferri perchlor. B.P., diluted with 5-10 vols, of 70 p.c. 

 alcohol, is added. The organisms may subsequently be stained by 

 treating for twelve to twenty-four hours with alcohol containing a 

 trace of gallic acid. 



When time is limited, or in the absence of any suitable means 

 ashore of keeping the contents of the tow-net in a healthy condition 

 for several hours while the various organisms are being sorted out, 

 it is advisable to resort to some wholesale method of quickly 

 preserving the whole of the catch. The following is a simple 

 method which I have employed for many years with considerable 

 success : — The receptacle to contain the catch consists of a glass 

 pickle-jar of some half-gallon capacity, with a good, deep, tight- 

 fitting cork. Through the cork two cleanly-cut holes, about three- 

 quarters of an inch in diameter, are bored, and into one of these a 

 piece of brass tubing six inches in length is tightly fitted, so as to 

 project on either side of the cork. To that end of the tube which 

 will project within the jar, a loose coil of wire, consisting of about 

 half-a-dozen turns, and about two inches diameter and four inches 

 long, is firmly soldered. Over the loose coil is securely fastened 

 to the tubing a small bag of fine muslin or bolting silk. The end 

 of the tubing outside the jar is bent at an angle like a spout. 

 Into the second hole is tightly fitted a stout japanned iron funnel, 

 having a rim eight to ten inches in diameter. Into this funnel 

 the contents of the " can " at the bottom of the tow-net is emptied 

 each time it is drawn inboard, and while the waste water flows 

 out through the brass tube, the little muslin or bolting-silk bag 

 prevents the escape of the animals, and the coil of wire keeps the 

 bag expanded and the animals from becoming jammed against 

 the tube by the outrush of water. 



If possible, some of the time between each haul of the tow-net 

 should be devoted to picking out from the collecting-jar, by means 

 of a piece of glass tube or pipette, any Hydromedusse or other 

 delicate organisms, which should be placed in a separate receptacle, 

 so that they may be treated by one of the processes already 

 described, as they would be injured by the rougher wholesale 

 method of preservation. The rest of the catch may then be 

 emptied into a smaller glass jar, and while stirring gently with a 

 glass rod, so as to keep the organisms on the move, a small 

 quantity of 4 p.c. formaldehyde is added. After stirring for about 

 five minutes allow the plankton to settle at the bottom of the jar. 

 "When the jar is not more than half filled with the plankton, pour 

 off as much of the fluid as possible and fill up with 4 p.c. 

 formaldehyde, giving a good stir round so as to thoroughly mix. 

 Each store jar should never be more than half filled with plankton ; 

 if the jar is then filled up to the top with the formaldehyde 

 solution, the organisms will keep all right. . It is necessary the 

 following day to pour off the 4 p.c. solution, and then fill up with 



