HISTORY OF ZOOLOGY. I 5 



sion of our knowledge was brought about. Of Swammer- 

 dam's writings attention should be called particularly to 

 " The Bible of Nature," a work to which no other of that 

 time is comparable, since it contains discoveries of great 

 accuracy on the structure of bees, May-flies, snails, etc. 

 Leeuwenhoek, finally, was a most fortunate discoverer in the 

 field of microscopic research, by him introduced into 

 science. Besides other things he studied especially the tiny 

 inhabitants of the fresh waters, the "infusion-animalcu- 

 les," a more careful investigation of which has led to a 

 complete reversal of our conception of the essentials of ani- 

 mal organization. 



The Dawn of Independent Observation. The great 

 service of the above-named men consists chiefly in this, that 

 they broke away from the thraldom of book-learning and, 

 relying alone upon their own eyes and their own judgment, 

 won for man what had been quite lost, the blessing of inde- 

 pendent and unbiassed observation. They spread the 

 interest for observation of nature over a wide circle so that 

 in the eighteenth century the number of independent natural- 

 history writings had increased enormously. There were 

 busy with the study of insect structure and development, 

 deGeer in Sweden, Reaumur in France, Lyonet in Belgium, 

 Rosel von Rosenhof in Germany; the latter besides wrote a 

 monograph on the indigenous batrachia, which is still worth 

 reading. But particularly the investigation of the infusoria 

 formed a favorite occupation for the learned and the laity, 

 as Wrisberg, von Gleichen-Russwurm, Schaffer, Eichhorn, 

 and O. F. Miiller. In most of the writings the religious 

 character of the contemplations of nature are extraordi- 

 narily emphasized, for since we find that among these 

 writers numerous clergymen, Eichhorn in Danzig, Graze in 

 Quedlinburg, Schaffer in Regensburg, had attained honor- 

 able positions, we have a sign that a reconciliation had 

 taken place between Christianity and natural science. As 

 a criterion of the progress made in comparison with the 

 earlier centuries, a mere glance at the illustrations is suffi- 

 cient. Any layman will at the first glance recognize the 



