CHAPTER VI 



THE BRANCH OF PROTOZOA OR PROTOZOANS. 



SECTION i. 



THE PROTOZOA CONSIDERED AS A BRANCH. 



As already stated on page 5, there are vast numbers 

 of beings which are so simple in their form and structure, 

 that naturalists are in doubt, in many cases, whether to 

 call them Plants, or Animals. 



In most cases they have neither mouth nor stomach ; 

 and with comparatively few exceptions, they are exceed- 

 ingly minute, and mostly microscopic. Many of them 

 are so small that they can be studied only by the most 

 skillful observers, aided by the most powerful microscopes. 



In a vast number of cases they are apparently no more, 



FIG. 732. 



Yeast-plant (Torula cerevisire) as developed during fermentation, 

 a, 6, c, d, successive stages of cell multiplication. 



and in many cases even less complicated in their structure 

 than this little plant which we call yeast, being mere 

 particles of mucous-like matter (sarcode or protoplasm). 



