206 H.OWRR1XG AND ITS CONSEQUENCES. 



its huge flower-stalk shoots forth (24), and the whole plant inevita- 

 bly perishes when the seeds have ripened. So, also, the Corypha, 

 or Talipot-tree, a magnificent Oriental Palm, which lives to a great 

 age and attains an imposing altitude (bearing a crown of leaves, 

 each blade of which is often thirty feet in circumference), flowers 

 only once ; but it then bears an enormous number of blossoms, suc- 

 ceeded by a crop of nuts sufficient to supply a large district with 

 seed ; and the tree perishes from the exhaustion. 



370. Flowering and fruiting, then, draw largely upon the plant's 

 resources, while they give back nothing in return. In these opera- 

 tions, as also in germination, vegetables act as true consumers (like 

 animals, 3G3), decomposing their own products, and giving back 

 carbonic acid and water to the air, instead of taking these materials 

 from the air. It is in flowering that they actually consume most. 

 In fruiting, although a large quantity of nourishment is taken from 

 the plants, this is mostly accumulated in the fruit and seed, in a con- 

 centrated form, for the future use of the new individual in the seed. 



371. The real consumption of nourishment by the flower is shown 

 by the action of flowers upon the air, so different from that of leaves. 

 While the foliage withdraws carbonic acid from the air, and re- 

 stores oxygen (346, 358), flowers take a small portion of oxygen 

 from the air, and give back carbonic acid. While leaves, therefore, 

 purify the air Ave breathe, flowers contaminate it; though, of course, 

 only to a degree which is relatively and absolutely insignificant. 

 This process is necessarily attended by the 



372. Evolution of Heat. When carbon is consumed as fuel, and 

 by the oxygen of the air converted into . carbonic acid, an amount 

 of heat is evolved directly proportionate to the quantity of carbon 

 consumed, or of carbonic acid produced. Precisely the same 

 amount is more slowly generated during the gradual decomposition 

 of the same quantity of vegetable matter by decay, — a heat which 

 is employed by the gardener when he makes hot-beds of tan, decay- 

 ing leaves, and manure, — or by the breathing of animals, which 

 maintains their elevated temperature (364). The conversion of a 

 given amount of carbon and hydrogen into carbonic acid and water, 

 under whatever circumstances it may take place, and whether slowly 

 or rapidly, generates in all cases the very same amount of heat. 

 Now, since flowers consume carbon and produce carbonic acid, acting 

 in this respect like animals, they ought to evolve heat in proportion 

 to that consumption. This, in fact, they do. The evolution of heat 



