386 BULLETIN OF THE BUSSEY INSTITUTION. 
No. 35.— Observations on Some of the Chemical Substances 
in the Trunks of Trees. By F. H. Storer, Professor of 
Agricultural Chemistry. 
It has often been assumed that starch stored in the tree before 
the advent of winter is the chief or even the sole source of the 
sugars of one kind or another which in cold countries appear in 
the spring in the sap of many forest trees. Other observers have 
suggested that a part, at least, of the reserve food in trees, exists 
there in the form of hemicelluloses which may be changed to sugar 
in due course. ‘This view finds support in the fact that some part 
of the hemicelluloses in wood are easily made soluble by the 
action of acids and alkalies; that much of the reserve food stored 
in cabbages and turnips and some other roots is palpably in the 
state of hemicelluloses, and that in the so to say historic in- 
stance of the course of germination of date-stones (and various 
other hard seeds) it has been noticed, by several distinguished 
observers, that the hemicelluloses of the seed serve to nourish 
the young shoot. 
The results of analyses made in this laboratory go to show 
that there is still much to be learned in respect to the reserye 
matters in the wood of trees, and they suggest the questions 
whether undue stress may not have been laid sometimes on the 
storing up of starch, and too little attention have been paid to 
the differences which really exist between those hexosans (such as 
mannans and galactans), which are known to be capable of sup- 
plying food to germinating plants and the comparatively speaking 
inert pentosans (xylan, for example), which abound in the wood 
of many trees. 
The analyses recorded below indicate that the quantity of re- 
serve starch stored in the trunks of trees is ordinarily not so 
large as has sometimes been stated. It is noticeable, withal, 
that the proportion of starch, in the woods thus far examined, 
varies less widely at different seasons than might have been sup- 
posed from statements which still pass current, in spite of the 
observations of several botanical investigators who have seen with 
the microscope that starch exists in the wood of trees not only in 
autumn and winter, but in the spring and summer also, and have 
suggested that the variations in the amount of starch contained 
