1 6 Introduction 



With such crude instruments as the early micro- 

 scopists could command they began to explore the world 

 over again. They looked into the minute structure of 

 everything — forms of crystals, structure of tissues, 

 scales of insects, hairs and fibers, and, above all else, 

 the micro-organisms of the water. These, living in a 

 transparent medium, needed only to be lifted in a drop 

 of water to be ready for observation. At once the early 

 microscopists became most ardent explorers of the 

 water. They found every ditch and stagnant pool 

 teeming with forms, new and wonderful and strange. 

 They often found each drop of water inhabited. They 

 gained a new conception of the world's fulness of life 

 and one of the greatest of them Roesel von Rosenhof , 

 expressed in the title of his book, ''Insekten Belusti- 

 gung'"^ the pleasure they all felt in their work. It was 

 the joy of pioneering. Little wonder that during a 

 long period of exploration microscopy became an end 

 in itself. Who that has used a microscope has not been 

 fascinated on first acquaintance with the dainty ele- 

 gance and beauty of the desmids, the exquisite sculptur- 

 ing of diatom shells, the all-revealing transparency of 

 the daphnias, etc., and who has not thereby gained a 

 new appreciation of the ancient saying, Natura maxime 

 miranda in mifiimis.] 



Among these pioneers there were great naturalists — 

 Swammerdam and Leeuwenhoek in Holland, the latter, 

 the maker of his own lenses; Malpighi and Redi in 

 Italy; Reaumer and Trembly in France; the above 

 mentioned, Roesel, a German, who was a painter of 

 miniatures; and many others. These have left us 

 faithful records of what they saw, in descriptions and 

 figures that in many biological fields are of more than 

 historical importance. These laid the foundations of 



*Belustigung = delight. 



t Nature is most wonderful in little things. 



