212 IIKCEMX RESEARCHES ON THE UESPIUATION 01' TLANTS. 



can be arrived at in this way, since the quantity of water of 

 vegetation contained in plants varies with the time of day, the 

 season, tlieir age, the places in which they grow, and the tem- 

 perature to wliich they are exposed. Besides, as soon as an 

 attempt is made to determine the relations which exist between 

 the matters containing proteine and the oxygen transformed by 

 them into acid gas, all comparison is liable to lead to erroneous 

 conclusions unless based exclusively on the weight of the organ 

 dried at a temperature which is kept uniform in all tiie experi- 

 ments ; for this reason the buds upon which the present ob- 

 servations were made were dried for twelve hours at a temperature 

 of 110° C. 



These first experiments upon the respiration of buds were 

 scarcely finished when the temperature fell rapidly, and their 

 vegetation remained stationary until the 15th of April, when it 

 again I)ecame very active, the temperature in the shade having 

 risen to 15° and 18° C. On the 20th of the same month each 

 of the buds of the trees previously examined had made a young 

 shoot, and these shoots were in their turn taken and made up 

 into little bundles, of the same weight as that of the bundles of 

 buds before mentioned, and placed under the same conditions as 

 the latter. The results were very analogous to and sometimes 

 identical with those obtained from the buds ; this will be seen 

 if the numbered examples in the following table (p. 213) are 

 compared with the corresponding numbers in that before given. 



If, instead of comparing the partial results given in this table, 

 we take the mean as term of comparison, the differences which 

 will be then found to exist are so small that we feel warranted in 

 stating that the buds and young shoots which succeed them, con- 

 sume, under the same conditions and for equal weights, an equal 

 quantity of carbon : that is to say, that the activity of their re- 

 spiration is the same. We have in effect, — 



Table the first : 69 grammes ; fresh buds = 1 2-55 grammes ; 

 dry buds = 240 c.c. carbonic acid. 



Table the second: 66 grammes; young shoots= 12-85 grammes; 

 dry shoots = 266 c.c. carbonic acid. 



2. The Respiration of Young Plants. 



Seeds, like buds, contain the fundamental rudimentary organs 

 of the plants which they spring from, and are provided with a 

 large proportion of living azotized matters : thus it is that during 

 their germination, if collected into masses, they consume their 

 own carbon, and give out sufficient heat to affect the commonest 

 thermometers. This function, already so active at the commence- 

 ment of germination, goes on with still greater intensity when the 

 seeds, disengaged from their episperm, spread out their cotyle- 



