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SOME METHODS OF PREPARING MARINE 

 SPECIMENS. 



By F. Martin Duncan, F.R.M.S., F.E.P.S., F.Z.S. 



iRead November 9th, 1920.) 



In few branches of Natural Science has the microscope been of 

 greater service than in the study of the countless forms of minute 

 plant and animal life which swarm in the sea. Without the help 

 of the compound microscope the true character of those 

 great sheets of grey mud, the Globigerina Ooze, which extend 

 far over the floor of the Atlantic, would never have been made 

 known, and the exquisite structure of the frustules of marine 

 diatoms and the fragile skeletons of radiolarians would have 

 remained hidden from our view ; while the extraordinary changes 

 of form through which many marine animals pass in the course 

 of their life would have remained unseen, and the complexity of 

 their life-histories unsolved. 



We are singularly fortunate in the rich marine fauna and flora 

 to be found all round our coasts, and although a great deal of 

 work has been done, yet little more than the fringe of the subject 

 has been touched, so that a wide and fruitful field for investigation 

 still awaits the microscopist. It is in the hope of stimulating 

 interest among our members, and more particularly with a view 

 to helping new students of microscoi^ic marine life, that I bring 

 to your notice some of those methods for preserving and pre- 

 paring marine forms of plant and animal life which have proved, 

 during a period of some twenty-five years of intermittent investi- 

 gations in Marine Biology, most practical and successful. 



The seaweeds well deserve the attention of the microscopist, 

 for there are a great number of small forms whose fruiting organs 

 are singularly beautiful objects under a two-thirds or half-inch 

 objective. Nor are they difficult to obtain : a morning's ramble 

 along the seashore after a heavy gale, more particularly during 

 the autumn and winter, at which season of the year so many 

 of the marine algae bear their fruiting organs, will often supply 

 sufficient material to keep the most ardent microscopist busy 

 for many a long winter evening. On returning from the shore 

 the seaweeds should, if possible, be overhauled and those speci- 

 mens selected which are intended for mounting as microscopic 



