SUMMARY AND REVIEW. 
carbon dioxide in a ceaseless round. All other 
foods used to sustain animal and plant life are 
so arranged by the processes of Nature as to be 
used again and again in a continuous circle, first 
by plants and then by animals, and then over 
again by plants, the circle to endure so long as 
the sun shines and the rain falls to promote its 
continuance. Many of these processes require 
much thought in order to understand the intri¬ 
cate workings of Nature. Those who under¬ 
take the study in earnest find it of special inter¬ 
est. Not the least interesting phase is the way 
in which nitrogenous foods, so necessary to ani¬ 
mal life, take their place in the continuous circle, 
and how, through the assistance of bacteria they 
are prepared to return to take part in the main¬ 
tenance of plant and vegetable life. 
Bacteria which assist in the sprouting of seeds 
and in other processes of Nature in farm and 
garden, form an interesting study, also. 
SUMMARY OF CHAPTER II. 
Mysteries with regard to diseases revealed by 
the microscope. 
Cell formation and the formation of the or¬ 
gans and systems. 
Health of the various organs and systems of 
the body dependent one upon another. 
Functions of some of the groups of cells. 
Derangement of the structure and its functions 
the cause of diseases. 
Bacteria as friends and as enemies. 
Application of the term bacteria. 
Length of time the term has been in use and 
the scientist who first distinguished the group 
from yeasts and moulds. His nationality. 
25 
Nature in 
Food Supply. 
