51 



haricot boan than for. the castor-oil phuit. Hut the sum obtained iu 

 oxperiinont No. i2 was very much below that stated in experinienl 

 No. 5. The duration of this experiment and its prolongation until 

 the api:)roach of the vegetating ])eriod ai)pears to me to account foi- 

 this ditt'erence. This hypothesis is supported by the results of (wperi- 

 ments Xos. 1 and 4, the first having lasted six days and the other less 

 than four. 



(5) By comparing the ratio -^■-' for similar expei'iments made in 



the light and in the dark, Ave see that there is alwaj^s a ditt'erence of a 

 quarter of the value of this ratio in favor of the dark; or, in other 

 words, a seed placed in the dark always exhales more carbonic acid 

 for the same quantity of oxygen absorbed than a seed kej)t in the 

 light, even although sometimes, as we showed in experiment No. 8, the 

 absolute quantity of carbonic acid exhaled is less in the light than it is 

 in the dark. Finally, while in the light the carbonic acid released 

 is always much less in quantity than the oxygen absorbed, the con- 

 trary may be the case in the dark, where the absolute amount of car- 

 bonic acid may even exceed the absolute quantity of oxygen, as is 

 proved in experiment No. 4, where the absorption of oxygen 87.36 

 corresponds to an exhalation of 42.54 of carbonic acid. 



(6) In order to consider the influence exerted upon the ratio -^^ by 



the nature of the grain itself under diiferent conditions as to light 

 and darkness, it is only necessary to consult the conclusions which 

 precede, and note the marked ditferences that distinguish the albumi- 

 nous and oily seed of the castor oil from the nonalbuminous and 

 starchy haricot bean. 



(7) The facts which precede complete the explanation already 

 given of the transformation of legumin into asparagin under the 

 influence of light. In general, the absorption of a greater quantity 

 of oxygen only assures the formation of asparagin in so far as the 

 amount of carbonic acid exhaled is less than the amount of oxygen 

 absorbed; since asparagin is poorer in carbonic acid and richer in 

 oxygen than legundn, all the conditions favorable to that formation 

 are to be found demonstrated in the results of experiment No. 4, with 

 seeds exposed to the light. It is very probable that a portion of the 

 oxA'gen which had disappeared and that was not found as carbonic 

 acid was absorbed by the albuminoids when forming asparagin, and 

 we know from other sources that this substance seems to form in the 

 majority of seeds during the process of germination. 



This absorption of oxygen during the period of- germination is 

 still greater in the castor-oil seed than in that of the bean. The oily 

 seed, therefore, seems to be more favored by nature from a i)hysio- 

 logical point of view. 



(8) We might be tempted to compare the ratio ^. '\ obtained during 



the time of germination, with the same ratio during the period of 

 vegetation. But the sum for the vegetating epoch has only been 

 precisely fixed in the dark, which for green plants is entirely an ab- 

 normal state. As, on the other hand, it is impossible to gauge exactly 



