LINNZUS AND NATURAL HISTORY 139 
The Organism.—In the time of Linnzeus the attention of 
naturalists was mainly given to the organism as a whole. 
Plants and animals were considered from the standpoint of 
the organism—-the external features were largely dealt with, 
the habitat, the color, and the general appearance—features 
which characterize the organism as a whole. Linnzus and 
Jussieu represent this phase of the work, and Buffon the 
higher type of it. Modern studies in this line are like addi- 
tion to the Systema Nature. 
Organs.—The first distinct advance came in investigating 
animals and plants according to their structure. Instead 
of the complete organism, the organs of which it is composed 
became the chief subject of analysis. The organism was 
dissected, the organs were examined broadly, and those of 
one kind of animal and plant compared with another. This 
kind of comparative study centered in Cuvier, who, in the 
early part of the nineteenth century, founded the science of 
comparative anatomy of animals, and in Hofmeister, who 
examined the structure of plants on a basis of broad com- 
parison. 
Tissues.—Bichat, the famous contemporary of Cuvier, 
essayed a deeper level of analysis in directing attention to the 
tissues that are combined to make up the organs. He dis- 
tinguished twenty-one kinds of tissues by combinations of 
which the organs are composed. This step laid the founda- 
tion for the science of histology, or minute anatomy. Bichat 
called it general anatomy (Anatomie Générale, 1801). 
Cells.—Before long it was shown that tissues are not the 
real units of structure, but that they are composed of micro- 
scopic elements called cells. This level of analysis was not 
reached until magnifying-lenses were greatly improved— 
it was a product of a closer scrutiny of nature with improved 
instruments. The foundation of the work, especially for 
plants, had been laid by Leeuwenhoek, Malpighi, and Grew. 
