FROM THE AIR BY THE LEGUMINOS.E 35 



to drain into the lower portions, and thence to all parts 

 of the leaf. 



(3) These albumen-producing hairs are sometimes situated 

 on the petiole, and often on every surface of the leaf, though 

 chiefly along the edges. 



If the formation and discharge of the albumen are to 

 be thoroughly understood, it is often necessary, in the case 

 of certain plants, to examine the seedling. It is not likely 

 that there is any essential difiference in structure between the 

 long and short hairs, for the production or non-production 

 of albumen is due to the presence of green matter in some 

 and its absence in others. The presence of green matter 

 depends on the amount of vigour present in the hair at the 

 start. The position which the hair occupies on the plant 

 determines the production of green matter, which varies in 

 quantity according to the flow of sap. 



The fact that nature apparently provides plants with 

 special means of absorbing nitrogen is in no way remark- 

 xible to Jamieson, in view of the sluggishness of nitrogen. 

 He further finds it quite rational that this absorption 

 should be restricted to certain of the youngest organs, since 

 from early youth onwards the plant needs practically the 

 whole of its nitrogen in order to construct its tissues. 



The existence of specialized albumen-producing hairs on 

 the young shoot and on the investment of the young flower 

 bud is thus an interesting and useful example of Nature's 

 way of adapting means to an end. It is just as difficult to 

 explain by what processes the chlorophyll converts nitrogen 

 into organic matter, as to demonstrate how leaves break 

 down carbonic acid. 



Jamieson concludes his work by saying he cannot affirm 

 the green matter in the leaves to be the same as that in 

 the hairs, and considers he has brought sufificient proof to 

 gain acceptance for his theories. 



Whatever the value of the researches of the Director of 

 the Aberdeen Agricultural Station may be, the theories of 



