t a good many chestnut trees
were dying in his vicinity, a number sufficient to have attracted
especial attention. He looked at the matter carefully, and decided that
there was a definite disease on these trees. He handed specimens over to
Doctor Murrill of the New York Botanical Garden; who worked out the
disease, and decided that it was a new fungus which was causing the
trouble. He named it _Diaporthe parasitica_, the name under which it is
generally known today, although there is some question as to whether
that is the one which should be applied to it. This, you remember, was
in 1904--in the fall.

The first publication which appeared on the disease was in 1906, as I
recall it. The publication which then appeared was Doctor Murrill's upon
his investigations. The disease has spread very rapidly since then, so
that today we know the disease in a general area indicated by the red
color on this map. The green area indicates in a general way the natural
distribution of the common chestnut. Since 1904 investigations upon the
geographical range of the disease have been carried on so far as to show
that the disease is now known over approximately the area indicated in
red on that map. The northern limits of the disease are perhaps in New
York State. Further east, it is known as far north as northern
Massachusetts, mainly in the western part, and it is also known in
Boston. There have been two or three cases of the disease found in the
Arnold Arboretum. On the west, we have two cases in West Virginia, and
the most southern station which I know of is in Bedford County,
Virginia. But those are isolated stations beyond the area which is
indicated here. I shall have a little more to say in regard to the
distribution.

Before speaking of that, I want to call your attention to a few points
in regard to fungi in general, points of common knowledge to all who
have studied fungi or mycology. A fungus is a kind of plant which does
not, on account of the absence of the green coloring matter, manufacture
its own food. It is a plant which has, in other words, no green foliage,
and as it has no green foliage, it must obtain its organic or elaborated
food from some other source. The fungi have very aptly been termed the
tramps of the vegetable kingdom, that is, they live on food prepared by
somebody else. They can take certain organic substances and change them
apparently into other organic matter which can be used by the plant. In
the