374 STUDIES IN SEEDS AND FRUITS 



in a paper entitled " Etude physiologique sur le d^veloppement 

 des fruits et des grains" [Comptes rendus, Kug-ast 24, 1908). 

 They are not concerned with the coloration of seeds, but they 

 are interesting from the light they throw on the conditions in 

 which it takes place. Selecting very young pods on the living 

 plant with their sides still in apposition, he removed part of 

 them by longitudinal sections, and found that they soon 

 formed a new suture, closed themselves in, and developed 

 normally. When, however, pods more advanced in growth 

 and with their inner surfaces no longer in contact were 

 experimented on, different results were obtained. By cutting 

 out portions of the sides of the pods so as to bring the young 

 seeds into direct communication with the outer air, it was 

 ascertained that the growth of the seeds was arrested, the fruits 

 falling ofF in about a week. The conclusions arrived at were 

 that for the normal development of the seed a confined 

 atmosphere {une atmosphere conjinie) is needed, and that one 

 of the functions of the pericarp is to maintain the internal 

 air at a certain stable composition. The green parts of the 

 pericarp, it is observed, decompose in light the carbonic acid 

 arising from the respiration of the seeds and prevent its 

 accumulation inside the fruit. Even in darkness the gas is 

 kept within certain limits by its slow diffusion from the fruit. 



As regards the failure of young pods when the seeds are 



exposed to the air through windows cut through the pericarp, 



it may be surmised that capsules with their cells or loculi 



distinct from each other would be rather more suitable for such 



experiments. When an opening is made in the side of an 



ordinary legume the whole contents are exposed to the outside 



air, whilst in a capsule, by confining the experiment to only one 



of the cells, the rest of the fruit would be relatively unaffected. 



The author's My own experiments on the green capsules of living 



on^te™^" plants of Scilla nutans occupied the period between the middle 



S^a *^ °^ °^ J"*^^ ^^^ *^^ beginning of August, and were limited to one 



nutans. cell only in each fruit, the other two being left untouched. 



The cell was so incised that the seeds in it were, freely exposed 



