and the respiration of the entombed plants is one reason why 

 eggs will not always remain "strictly fresh," and why cold 

 storage will prolong the period of their freshness. 



The difference between green and black tea is largely owing 

 to the fact that, in the case of the latter, microscopic plants have 

 been allowed to respire among the moist leaves of the tea plant 

 until a critical point is reached, when the plants are killed and 

 the respiration stopped. A well regulated banquet must termi- 

 nate with cheese and black coffee; but is the cheese Camembert, 

 Roquefort, Xeufchatel, Brie, or Schweitzer ? That depends upon 

 the kind of plants that respired within the cheese during the 

 process of its ripening. Formerly it was not thought possible 

 to produce a given kind of cheese except in a given native 

 locality ; but this is no longer so, for, since it has been known 

 that the difference depends upon the activity of plants, these little 



manufacture a given kind of cheese. 



the fact that carbon-dioxide and water are not the only by-prod- 

 ucts of respiration. Many other substances result, the discus- 

 sion of which would lead us into technicalities beyond the 

 scope of the present lecture. 



But someone may be raising the question of the value of 

 plants in the sick room. It is hardly necessary to more than 

 mention the subject, for now that we know that plants are con- 

 animals, it is at once recognized that they would have the same 

 kind of an effect on the air of a room that a person or a burning 

 gas jet would have, though possibly not to the same degree. If 

 the plants were abundantly supplied with green leaves, and were 

 well exposed, even to bright diffused sunlight, they would sup- 

 ply an insignificant amount of oxygen to the air. But at the 

 same time they would be sources of carbon dioxide. And when 



flowers, often not over fresh, and that flowers respire more vigor- 

 ously than any other part of a plant except germinating seeds, we 

 do not need to be further enlightened as to their power of puri- 



