CHAPTER VIII. 
PLANTS AND ANIMALS. 
IF an argument were needed in favour of the study 
of botany, no better could be urged, or required, than 
a statement of the obligations which man, in common 
with all animals, is under to the vegetable kingdom. 
There is no necessity, and there is no possibility, of 
exaggerating this obligation, for man himself, “the 
lord of creation,” is absolutely dependent upon plant- 
life for his existence. Were all vegetable-life with- 
drawn from this globe, animal-life would quickly 
cease, SO intimate is the connection between animals 
and plants. We have seen in our second Chapter 
how the plants consume the poisonous carbon with 
which the respiration of animals has polluted the air, 
and how they give out the oxygen which is abso- 
lutely necessary for our existence. This explains 
why large towns are less healthy than the country— 
an explanation which until recently the town popu- 
lations, or, rather, the municipal authorities, have 
ignored; and so the towns have gone on extending 
their boundaries, covering with bricks and mortar 
the surrounding fields. and lanes, cutting down trees, 
and otherwise shutting out the country and decreas- 
ing the healthiness of the city. “Ifa man walk in 
