466 
ABSTKACTS AND GLEANINGS IN BOTANY, ' 
y j 
It is but slightly soluble in cold water, which dissolves only 0-51 per cent., but 
boiling water dissolves it with facility, absolute alcohol scarcely at all, and it is 
quite insoluble in ether. 
The aqueous solution has a slightly bitter taste, it deviates the plane of pola¬ 
rization to the left, it precipitates neither acetate nor sub-acetate of lead, and 
gives no coloration with ferric chloride. Boiled with weak sulphuric or hydro¬ 
chloric acid, it turns thick owing to the separation of a resinous substance of a 
slightly bluish colour, emitting, at the same time, an odour of Yanilla. The 
precipitate darkens in colour by drying; it dissolves in soda, forming a yellowish 
solution, from which it is again thrown down by acids; heated—it evolves a very 
aromatic odour. The liquor filtered from this precipitate is dea^iro-rotatory 
and contains sugar, the presence of which may be recognised by cupro-potassic 
tartrate. 
Coniferine presents a characteristic reaction. Whilst Salicine is turned red 
by concentrated sulphuric acid, Coniferine turns a deep violet, on adding after¬ 
wards a little water, a precipitate is formed, which colours the liquid a deep 
‘ indigo blue, and which is probably the same substance as mentioned above. 
Cold hydrochloric acid dissolves Coniferine without change of colour, but if 
the solution formed is heated and evaporated, the same indigo-blue precipitate 
is formed. 
Sulphuric acid is a good reagent for recognizing this substance. It is sufficient 
to touch a fresh-made cut in a tree of the family Coniferse, in order to ascer¬ 
tain the presence of Coniferine .—Journal f, Prakt. Chemie, t. xcvii. p. 243. 
■Why do the Lteaves Pall? 
Not long since it would have been impossible to have given a satisfactory 
reply to a question, which is frequently asked, “Why do the leaves fall?” 
True, there were plenty of reasons cited, but they were for the most part 
merely hypothetical. Some said, that as the leaves were gorged with sap, 
their functions became in consequence impeded, and at last the leaves died 
and were pushed off from the tree by the current of the sap. Others said it 
was the bud, that nestled in the axil of the leaf, that quietly removed the parent 
leaf as itself increased in bulk,—a strange theory, when it is considered how 
many more leaves there are than buds ! A third notion was, that as the leaves 
died mortification ensued, a line of demarcation was formed, and the dead por¬ 
tions became separated from the living—a notion evidently derived from the 
experience of the surgeon rather than from that of the vegetable anatomist. 
Another of these guesses, and one apparently which finds much favour with 
compilers of “ popular ” books, attributes the fall of the leaf to an incrustation 
or deposit of earthy matters in the cells of the leaf in autumn ; this goes on, 
according to our theorists, to such an extent, that the cells become blocked up, 
lose their powers, hence dry up, shrivel, and fall to the ground,—true enough, 
but not sufficient to account for all the phenomena. On turning from these 
speculative explanations to others offered in more recent times by scientific ob¬ 
servers as the result of personal observation, we find so great a conformity of 
statements in all more important particulars, that it can h^ardly be doubted that 
we can now, at least in a general way , answer the question as to why the leaves 
fall. Several independent observers, among whom Dr. Inman, of Liverpool, is 
one, have arrived at the conclusion, that the fall of the leaf is clue to the forma¬ 
tion of a layer of cells, arranged in a plane different from that of the rest of 
the tissues, thus gradually severing the leaf from its support, much as a knife- 
blade would do, and moreover serving as a thin skin to protect the surface of 
what would, otherwise, be an open wound. The cells of this dividing layer, as 
shown by Inman and confirmed by Mohl, contain a quantity of starch, a sub- 
