BULLETIN OF THE BUSSEY INSTITUTION. hi 
As corroborating the evidence set forth in the table above given 
which relates to mannan in pine wood, attention should again be 
called to the results of efforts previously made to determine quan- 
titatively the amounts of mannan contained in samples of pine 
wood cut respectively in late August and in the middle of De- 
cember, as has been explained in the previous number of. this 
Bulletin (Volume 8, page 36). In those trials it appeared that 
while 3.61 per cent. of mannose was obtained from the August 
wood, only 1.86 per cent. was yielded by the wood of the tree 
cut in December. Even those preliminary, isolated trials went to 
show that pine trees contain much more mannan in late summer 
than they do in early winter, and this inference has been borne 
out by new trials, with these particular samples of woods, made 
by the new method of testing and reported in the table under the 
dates ‘‘late August, 1900,” and December 14,1901. Manifestly, 
this inference has been strengthened greatly by the whole series 
of results obtained by the new method of testing as given in the 
table. 
There can, I think, be little doubt that when properly studied 
the fact that pines, and presumably other coniferous trees, con- 
tain in late summer and early autumn a large store of the reserve 
food mannan may serve to explain a number of points relating to 
the physiology of coniferous evergreens that are now somewhat 
obscure. Possibly it may be true that this store of reserve food 
is used directly for the formation of new leaves even in the autumn 
to supply the place of those which are to fall at that season; or 
the mannan may serve for the nourishment and growth during 
winter of those leaves which with the advent of spring are to 
push off the old leaves which are then seen to fall. ‘The very 
fact that the conifers are ‘‘ evergreen” in rigorous climates may 
perhaps depend on the power of their leaves, when cold weather 
sets in, to draw upon the store of reserve matter that was accu- 
mulated by the tree during the summer. 
There is one apparently well established rule of horticultural 
practice — widely held in England and in the Northern United 
States —that the best time to transplant coniferous trees is in 
the early autumn, which may perhaps depend absolutely on the 
abundance of mannan in such trees at that season. I have noticed 
even that one prominent nursery man in the vicinity of Boston 
