December ] ROOMS CAMELLIAS. 307 



and give out oxygen by their under ones, thereby tending to 

 purify the air, in as far as animal life is concerned, because 

 carbonic acid gas is pernicious to animals, and oxygen is what 

 that life requires. It is in the light, however, that these 

 operations are carried on, for in the dark, plants give out car- 

 bonic. It does not appear that any of the scentless products 

 given out by plants are injurious to human beings, because 

 those who live among accumulated plants are not less healthy 

 than others, but rather enjoy more uninterrupted health, which, 

 of itself, is a sufficient recommendation for all to spend their 

 leisure moments in so healthful and rational an employment. 



