210 ACTION OF DISC. [BOOK n. 



flowering are the same ; the phenomena are in both cases 

 also very similar. 



When a germinating seed has acquired the necessary degree 

 of heat and moisture, it abstracts from the air a portion of its 

 oxygen, and gives out an equal quantity of carbonic acid 

 gas ; but as one volume of the latter gas equals one volume 

 of oxygen, it is evident that the seed is, in this way, deprived 

 of a part of its carbon. Some changes take place in the 

 albumen and cotyledons ; and, finally, the fsecula that they 

 contained is replaced by saccharine matter. In like manner, 

 a flower, while expanding, robs the air of oxygen, and gives 

 out an equal volume of carbonic acid ; and a sugary matter 

 is also formed, apparently at the expense of the faecula of the 

 disc or petals. 



The quantity of oxygen converted into carbonic acid in 

 germination is, cateris paribus, in proportion to the weight of 

 the seed ; but some seeds absorb more than others. Theodore 

 de Saussure has shown that exactly the same phenomenon 

 occurs in flowers. 



Heat is a consequence of germination ; the temperature is 

 also augmented during flowering, as has been proved by 

 Theodore de Saussure in the Arum, the Gourd, the Bignonia 

 radicans, Polyanthes tuberosa, and others. 



The greater part of the saccharine matter produced during 

 germination is absorbed by the radicle, and transmitted to 

 the first bud of the young plant. Dunal is of opinion that 

 the sugar of the nectary and petals is, in like manner, con- 

 veyed to the anthers and young ovules; and that the free 

 liquid honey, which exists in such abundance in many flowers, 

 is a secretion of superabundant fluid ; it can be taken away, 

 as is well known, without injury to the flower. 



This opinion will probably be considered the better 

 founded, if it can be shown that the disengagement of caloric 

 and destruction of oxygen are in direct relation to the 

 development of the glandular disc, and also are most consider- 

 able at the time when the functions of the anthers are most 

 actively performed. 



In no plants, perhaps, is the glandular disc more developed 

 than in Arums ; and it is here that the most remarkable 



