96 BIOLOGY AND ITS MAKERS 



Lyonet's researches. Roesel, in Germany, Reaumur, in 

 France, and De Geer, in Sweden, were all distinguished ob- 

 servers in this line. Their works are voluminous and are 

 well illustrated. Those of Reaumur and De Geer took the 

 current French title of Memoircs pour servir a I'Histoire des 

 Insectes. The plates with which the collected publications 

 of each of the three men are provided show many sketches 

 of external form and details of external anatomy, but very 

 few illustrations of internal anatomy occur. The sketches 

 of Roesel in particular are worthy of examination at the pres- 

 ent time. Some of his masterly figures in color are fine 

 examples of the art of painting in miniature. The name of 

 Roesel (Fig. 28) is connected also with the earliest observa- 

 tions of protoplasm and with a notable publication on the 

 Batrachians. 



Reaumur (Fig. 29), who was distinguished for kindly 

 and amiable personal qualities, was also an important man 

 in his influence upon the progress of science. He was both 

 physician and naturalist; he made experiments upon the 

 physiology of digestion, which aided in the understanding of 

 that process ; he invented the thermometer which bears his 

 name, and did other services for the advancement of sci- 

 ence. 



Straus-Durckheim's Monograph on Insect Anatomy. 

 Insect anatomy continued to attract a number of observers, 

 but we must go forward into the nineteenth century before 

 we find the subject taking a new direction and merging into 

 its modern phase. The remarkable monograph of Straus- 

 Diirckheim represents the next step in the development of 

 insect anatomy toward the position that it occupies to-day. 

 His aim is clearly indicated in the opening sentence of his 

 preface: "Having been for a long time occupied with the 

 study of articulated animals, I propose to publish a general 

 work upon the comparative anatomy of that branch of the 



