CHESTNUT BARK DISEASE. 413 
of the field has not disclosed any fungous disease that seems 
to be importantly connected with the condition of the trees.” 
NATIVE HOME OF THE FUNGUS. 
General Considerations. Previous to the work of Merkel and 
Murrill, no one had ever, so far as known, collected or 
described the true chestnut blight fungus. Its sudden and 
destructive appearance naturally leads to the question,—Where 
did it come from? Murrill has not tried to solve this problem, 
although we understand he at first believed it to be a native 
species. The writer is the only one who, *claiming it a native 
species, has attempted to give definite reasons for the belief, 
and an explanation of its sudden and aggressive development. 
Others have come forward with the suggestion that it is an 
introduced parasite, brought in accidentally, either from Japan 
or Europe. They have been led to their belief apparently 
largely because the blight was reported at first from-a restricted 
region around New York City, and has apparently since then 
spread from this center into the regions in which it is now 
known. We shall consider in the following paragraphs each 
of these possible habitats for this fungus. 
Japan. Metcalf has suggested most definitely that the fungus 
originally came from Japan, and Marlatt (31), following this 
suggestion, gives the blight as one of the most striking examples 
of “why we need a national law to prevent the importation 
of insect-infested and diseased plants.” Metcalf’s (33, P- 4) 
first statement concerning the native home of this fungus is as 
follows: “The immunity of the Japanese chestnut, together 
with the fact that it was first introduced and cultivated on 
Long Island and in the very locality from which the disease 
appears to have spread, suggests the interesting hypothesis that 
the disease was introduced from Japan.’ So far, however, no 
facts have been adduced to substantiate this view.” Later, 
Metcalf and Collins (36, p. 46) say: “Investigations are in 
progress to determine the origin of the bark disease in America, 
and the details regarding its spread. The theory advanced in 
the previous publication of this Bureau that the Japanese chest- 
nuts were the original source of infection has been strengthened 
by many facts. It lacks much of demonstration, however, and 
t 
