TRANSACTIONS AND PROCEEDINGS 



BOTAMCAL SOCIETY OF EDINBURGH. 



SESSION LXII. 



Addeess delivered at the opening of the Session 

 BY Professor A. P. Aitken, M.A., D.Sc, President of 

 the Society. — 11th November 1897. 



At the meeting of the Society at this time last year I 

 chose as the subject of my address " The Nitrogenous 

 Food of Plants," for the reason that it was a subject in 

 itself interesting, and on which our knowledge was being 

 rapidly developed, and also because, in treating it from a 

 historical point of view, I might prepare the way for other 

 papers of a practical kind on that subject that were to be 

 read before the Society, 



The attention of the fellows was chiefly directed to 

 the somewhat recent discovery that leguminous plants, 

 and more especially those of the sub-order Papilionacea?, 

 possessed, in a remarkable manner, the power of assimilating 

 the free nitrogen of the air and of converting it into their 

 own albuminoid tissue. The interest attached to this dis- 

 covery was greatly enhanced from two causes — first, because 

 authorities of the highest repute in the domains of botany, 

 chemistry, and agriculture, had, after what seemed to be 

 satisfactory and complete investigation, considered that 

 they were warranted in making the pronouncement that 

 plants did not possess that power ; and in the second 

 place, that when, after fifty years' negation, it was at length 

 put beyond doubt that leguminous plants did possess that 

 power, it was shown, at the same time, that they possessed 

 it, not in themselves, but only when their life were 



TKANS. BOX. SOC. EDIN. VOL. XXI. F 



