ele) BIOLOGY AND ITS MAKERS 
Lyonet’s researches. Roesel, in Germany, Réaumur, 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 Réaumur and De Geer took the 
current French title of Mémoires pour servir & 7 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. 
Réaumur (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 
