116 KECORD OF CURRENT RESEARCHES RELATING TO 



Formation of Albumen in the Plant.* — A careful series of ex- 

 periments has been carried on by A. Emmerling, in the " Versuchs- 

 station " at Kiel, for the purpose of determining the place and mode 

 of formation of the nitrogenous constituents of plants. The plant 

 selected was the common bean, Vicia Faba, the different parts of 

 which were examined at various stages of growth. 



With regard to the presence of nitric acid, the results arrived at 

 were that this substance is at no period of development present in any- 

 considerable quantity in the leaves; nor is it present in the flowers, 

 fruits, seeds, or pericarp, while the stems and roots contain it in dif- 

 ferent proportions. The conclusion is hence derived that the leaves 

 are especially the part where the nitric acid absorbed from the soil 

 undergoes transformation. 



The very extended researches on the presence of amide in the 

 various parts of plants gavq the following results : — In the mature 

 leaves the amides remain nearly constant during the entire later 

 period of development of the plant ; younger leaves are richer in these 

 substances than older leaves. The proportion of amide in flowers, 

 branches, and buds is relatively large, considerably exceeding that in 

 older, and two or three times the amount in younger leaves. The 

 flowers contain a larger proportion in an early stage than after they 

 are fully unfolded. The amide not only accumulates in the ovules, 

 but the petals and sepals also contain a considerable quantity. Fruits 

 and seeds are, in their early stages of development, comparatively 

 very rich in amides ; but the proportion decreases with the growth of 

 the seeds. The stem is at all times comparatively poor in this sub- 

 stance, and the lower woody leafless portion is the poorest, the 

 amount increasing both towards the summit and in the root. The 

 quantity in the root is, however, but small ; there is more in the 

 lateral roots than in the tap-root. 



The explanation suggested of these facts is as follows : — It is seen 

 how qviickly the nitric acid which is absorbed out of the soil into all 

 parts of the stem and root disappears in the leaves or other green 

 parts, or those which are growing rapidly; so that it is rare that 

 even traces of it are to be detected in these spots. It is therefore 

 scarcely questionable that it is chiefly in the green leaves that the 

 nitrates are transformed into nitrogenous organic compounds, the final 

 result of these transformations being the production of albumen. Even 

 if the small quantities of ammonium salts absorbed through the roots 

 take part in this result, the part they play is very subordinate to that 

 of the nitrates. The final change to which the nitrates are subjected in 

 the leaves is probably their decomposition by vegetable acids. The 

 distribution of the amides follows a simple law, which may be thus 

 stated: — ^Those parts of the plant which are in active growth and 

 increase of mass are richer in amide than the older mature parts. 



Composition of Chlorophyll. t — From the fact that chlorophyll loses 

 its power of decomposing carbonic acid with the death of the part 



* ' Landwirthschaftliche Versuchs-stationen,' xxiv. (1879) p. 113 ; see ' Natur- 

 forscher,' xii. (1879) p. 418. 



t 'Zeitschr. fiir pbysiol. Chemie,' iii. (1879) p. 339; see ' Natur forscher,' xii. 

 (1879) p. 391. 



