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PRESIDENTS ADDRESS. 
odour the name of some prominent flower by which it was given 
out. But lately an attempt has been made in 1 The Natural History 
of Plants,’ by Anton Kernel 1 von Marilaun, edited by Prof. Oliver, 
to classify floral scents according to their chemical properties; which 
however the writer says must be regarded only as a preliminary 
outline. 
Por the purpose of distinguishing such scents, they are divided 
into five groups, viz. : the indoloid, aminoid, benzoloid, paraffinoid, 
and terpenoid scents. In the first group, the indoloid scents are 
those volatile substances which arise from the decomposition of 
albuminous compounds. These scents resemble that of decaying 
animal matter, and attract flesh-eating Beetles and Flies ; the 
enticement of this smell of putrefaction being often aided by 
colouring which resembles flesh or rotting fruit. Among the 
plants which emit this indoloid scent are Aristolochias, Stapelias, 
and Arums, and as showing the great distance from which insects 
are drawn by such odours, it may be mentioned that in a single 
spathe of Dracvnculus vulgaris there were found 250 Carrion 
Beetles belonging to eleven different species. We are not therefore 
surprised to read that emanations from this Arum are extremely 
inconvenient, producing giddiness, headache, and vomiting. 
Under the name of aminoid scents are comprised substances 
which diffuse into the air, and have an amine as their foundation. 
These give to the Hawthorn its scent, as well as to the Chestnut, 
Evening Primrose, and Flowering Ash. 
The third group, that of the benzoloid scents, is composed of 
such as are formed from the so-called aromatic bodies; they are 
compounds with a benzole nucleus, in which the hydrogen atoms of 
the benzole are replaced by alcohols and acid radicals. These scents 
are found in the flowers of Pinks, Heliotrope, Lilac, Mignonette, 
and Honeysuckle, and many of them in flowers of widely differing 
genera ; thus we have the violet scent in the Stocks, the Clove scent 
in the Narcissus and in some Orchids, and the Vanilla scent in the 
Heliotrope, Petasites fragrans, Nigritella and Linncea borealis. It 
is worthy of note, that many of the flowers which have intermittent 
scents are to be found in this group, e.g., the Catchfiies, which emit 
