48 TRANSACTIONS AND PROCEEDINGS OF THE [Sess. Lxix, 
December 1891, on ‘‘ The Roots of Grasses in Relation to 
their Upper Growths.” (with two plates). On the 14th 
November 1895 he was elected President of the Botanical 
Society; and on retiring, on 12th November 1896, gave a 
Presidential Address, on “ The Nitrogenous Food of Plants.” 
At the close of his year of office he was re-elected president 
for another year; and at its close, on the 11th November 
1897, his Presidential Address was on “Symbiosis: The 
power possessed by certain leguminous plants of assimilating 
the free nitrogen of the air, and of converting it into their 
own albuminoid tissue.” On the 14th January 1897 he 
exhibited an apple, showing carpellary proliferation; and on 
the 10th March 1898, he read a paper on ‘* The Relation 
between the Colour of Daffodils and Composition of the Soils 
in which they are grown.”’ ‘These seem to include all his 
contributions to our “ Transactions” ; but the great amount of 
work which he had to perform in other relations, particularly 
in connection with the Highland and Agricultural Society, 
prevented him from giving that attention to purely botanical 
investigation, which in his hands would certainly have been 
fertile in result. 
Dr. Aitken was an original member of the Scottish 
Alpine Botanical Club, and held the appointment of minstrel 
during all the years of his membership. He was a man 
of most genial and happy temperament, and his presence 
was always much appreciated by the members. During the 
latter years of his life, when, owing to delicate health, he was 
unable to be present, he was much missed. He was a 
delightful singer, with a sweet and sympathetic voice, and 
was the author of many botanical songs, which were much 
enjoyed by the club. He was a good all-round botanist ; and 
the excursions on the Scottish mountains, which usually 
lasted for about a week, were much enjoyed by him. He 
was present on that memorable occasion in Glen Spean, when 
the club discovered, for the second time in Britain, that rare 
plant Saxifraga cespitosa, which had, about fifty years before, 
been discovered on Ben Aan, but the exact locality of which 
had been quite lost sight of, till it was refound by two or 
three of the members of this club growing in great beauty 
and luxurianee. He was also at a meeting at Braemar, when 
the club discovered that very rare plant Sagina Boydii, 
