SCIENCE 
Fray, May 10, 1912 
CONTENTS 
The Fungus of the Chestnut-tree Blight: PRo- 
FESSOR W. G. FARLOW .....----+++ee+e- 
More Trouble for the Systematist : PROFESSOR 
CG. G. NUTTING .......--..--------- sees 722 
Henry James Clark—Teacher and Investi- 
gator: DR. FREDERICK TUCKERMAN ....... 725 
Scientific Notes and News .......+.++++++++ 731 
University and Educational News .......--- 735 
Discussion and Correspondence :-— 
Non-Euclidean Geometry in the Encyclo- 
pedia Britannica: PROFESSOR GEORGE 
Bruce Haustep. Pearl and Jennings on 
Assortative Conjugation in the Protozoa: 
Dr. J. ARTHUR Harris. ‘‘ The Passing of 
the Slime-moulds’’: PRoressor T. H. Mac- 
BRIDE 736 
Scientific Books :-— 
Milham’s Meteorology: C. A. Probleme der 
physiologischen und pathologischen Chemie: 
PROFESSOR LAFAYETTE B. MENDEL. The 
Lower Cretaceous Deposits of Maryland: 
Dr. F. H. KNownron. Blatchley’s Wood- 
land Idyls: Dr. N. BANKS. Holmes’s Evo- 
lution of Animal Intelligence: PROFESSOR 
Joun B. Watson. Longstaff’s Butterfly 
Hunting in Many Lands: Dr. F. HB. Lutz . 743 
The Talking Dog: Harry Mites JoHNson . 749 
List of Generic Names for the ‘‘ Official List 
of Zoological Names’’: Dr. CH. WARDELL 
Simi soscosocooecneoouvevodsGG9C0KN G0 751 
Special Articles :— 
@nothera nanella, Healthy and Diseased: 
ProFessor Huco DE VRIES. Behavior of 
Spermatozoa in Plasma: Proresson Max 
WOES. soacescoaccusgoocoNocs DD0ODbODUE 
Societies and Academies :-— 
Research Workers in Experimental Biology, 
Washington: Dr. LEwis W. Fetzer. The 
Helminthological Society of Washington: 
Dr. Maurice ©. Haunt. The American 
Philosophical Society 
BMSS, intended for publication and books, ete., intended for 
raview should be sent to the Editor of Science, Garrison-on- 
Hudson, N. Y- 
THE FUNGUS OF THE CHESTNUT-TREE 
BLIGHT * 
Tue disease of chestnut trees now 
causing serious injury in the eastern states 
was first noticed about the year 1904 in 
the vicinity of New York and is believed 
to be due to the growth of a hitherto un- 
known fungus described by Murrill in 1906 
under the name of Diaporthe parasitica. 
The question naturally arises: Is the Dia- 
porthe a native species of this country 
which had escaped the observation of my- 
ecologists, or is it an introduced exotic spe- 
cies? If it is a native species we must next 
ask how it happens that so severe an epi- 
demic has appeared suddenly, for, if the 
fungus has always existed here, the impor- 
tant practical question is: What temporary 
conditions have arisen which have enabled 
it to increase at a rate previously un- 
known? Although there are some vague 
references to diseased chestnut trees in 
agricultural journals published a good 
many years ago, there is nothing in them 
to warrant us in believing that a disease at 
all comparable with the present chestnut 
epidemic ever prevailed here. One thing, 
at least, is certain. Had there been within 
the last fifty or sixty years a disease of 
chestnuts in the region now devastated 
similar to the present epidemic, there would 
have been left no large trees to be attacked 
now. 
In general it may be said that when a 
disease due to a fungus appears suddenly 
and with great severity, the chances are 
that it is owing to the introduction of some 
exotic species which, although it may not 
1Paper read April 19, 1912, before the Amer- 
ican Philosophical Society, Philadelphia. 
