132 Germany. 
In zodlogy the early writers began with a description 
of the biology of game animals. Next, interest in forest 
insects became natural and in 1818 Bechstein in his En- 
cyclopezdia devoted one volume (by Scharfenberg) to the 
natural history of obnoxious forest insects. Toward the 
middle of the century with the cultivation of forests and 
especially the planting of large areas with single species, 
insect pests increased, hence the interest in the life 
histories of the pests grew and gave rise to the cele- 
brated work by Ratzeburg, “Die Waldverderber und 
Ihre Feinde” (1841). A number of similar hand-books 
on insects and on other zodlogical subjects followed ; the 
last, a most complete work on insects, being still based 
on Ratzeburg’s work is that of Judeich and Nitzsche, in 
two volumes (1895). Of course, the general works on 
forest protection always included chapters on forest 
entomology. The first of these text-books on forest pro- 
tection was published by Laurop (1811), and others by 
Bechstein, Pfeil, Kauschinger and recently by Hess 
(1896), and Fiirst (1889). 
Knowledge of the soil was but poorly developed in 
the encyclopedic works of the earlier part of the period. 
Not till Liebig’s epochmaking investigations was a 
scientific basis secured for the subject. Then became 
possible the improvements in the contents of such works 
as Grebe (1886), Senféi (1888), and of Gustav Heyer, 
whose volume (Lehrbuch der Forstlichen Bodenkunde 
und Klimatologie, 1856), well records the state of 
knowledge at that time. But only since then has this 
field been worked with more scientific thoroughness by 
Ebermayer, Schreder, Weber, Wollny and by Ramann, 
