LTNN^US AND NATURAL HISTORY 139 



The Organism. — In the time of Linnaeus 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 — featun 

 which characterize the organism as a whole. Linnaeus and 

 Jussieu represent this phase of the work, and Buffon tin- 

 higher type of it. Modern studies in this line arc like addi- 

 tion to the Systema Naturce. 



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. Thissteplaid the founda- 

 tion for the science of histology, or minute anatomy. Bichat 

 called it general anatomy (Anatomic Caicnilc, 1801). 



Cells. — Before long it was shown thai 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 wen- 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. 



