SEPTEMBER 6, 1918] 
November 2. 
J. H. Barnhart. 
UNIVERSITY AND EDUCATIONAL 
NEWS : 
A BEQuest of $5,000 was made to Cornell 
University by Dr. William M. Polk, dean of 
the Medical College, who died on June 23. 
His purpose in making it was to continue the 
John Metealf Polk scholarship in medicine. 
A FELLOWSHIP in applied chemistry, of the 
annual value of £200, has been established at 
Glasgow University by the trustees of the 
Ferguson Bequest Fund. 
Proressor Raymond Binrorp, head of the 
department of zoology at Earlham College, 
Indiana, has been elected president of Guil- 
ford College, North Carolina. 
THE vacancy in the deanship of the medical 
college of Cornell University has been filled 
temporarily by the appointment of Walter 
Lindsay Niles, M.D., 1902, who will act as 
dean through the summer. Further action 
will be taken by the trustees in the autumn. 
Dr. A. J. Bicyry, on leave from Moores Hill 
College, has been appointed associate professor 
of zoology in Syracuse University for the en- 
suing year. Irving H. Blake, A.M., instruc- 
tor in Syracuse University has been appointed 
assistant professor of zoology in the Univer- 
sity of Maine. 
Dr. Ivan E. WaAuury, who was recently ad- 
vanced to an associate professorship in the 
school of medicine of Marquette University, 
has been appointed acting professor and head 
of the department of anatomy in the Univer- 
sity of Colorado school of medicine. 
At Glasgow University Dr. Thomas Walm- 
sley has been appointed lecturer in anatomy, 
with special reference to embryology. Mr. 
A. MeL. Watson has been appointed lecturer 
in physiology, with special reference to histol- 
ogy. Dr. John McL. Thompson has been ap- 
pointed lecturer in botany, with special refer- 
ence to plant morphology. 
SCIENCE 
‘*Plants as insect traps,’’ by Dr. 
247 
DISCUSSION AND CORRESPONDENCE 
THE PREVENTION OF ROPE IN BREAD 
Durie the course of an investigation of the 
physical and chemical properties of bread, 
which is being carried on by officers of the 
Sanitary Corps under my direction, our at- 
tention has been drawn to ropy bread. The 
development of rope at present causes a seri- 
ous loss of wheat and leads to much annoyance 
and uncertainty in the manufacture of bread. 
Quite recently Lieutenant E. J. Cohn has 
made certain observations which, if they could 
be made widely known, might greatly aid in 
controlling the present epidemic. Accordingly 
I venture to report upon them here. 
The familiar practise of adding acid to the 
dough as a means of checking the development 
of rope turns out to depend upon the fact that 
what seems to be the common cause of the con- 
dition, the growth of B. mesentericus, can not 
take place in bread at a greater hydrogen ion 
concentration than 10°N. At the present time 
the addition of wheat substitutes in bread-ma- 
king complicates the situation in two ways; 
first, because such substances commonly pro- 
duce a less acid bread, and, secondly, because 
it is more difficult to find out what quantity 
of acid is desirable on account of the con- 
stantly changing conditions. 
It is possible, however, to measure the hy- 
drogen ion concentration of bread by the addi- 
tion of the ordinary solution of methyl red 
(0.02 per cent. in 60 per cent. alcohol) to the 
freshly cut surface of the loaf. Three or four 
drops of the indicator should be placed upon a 
single spot and five minutes should be allowed 
to pass. Then, if.the color is a full red with- 
out an orange nuance, the hydrogen ion con- 
centration is approximately 10°N, or more. 
If an orange tint develops, greater amounts of 
acid should be added to successive batches of 
dough until the test with bread just gives the 
desired color. Our experience seems to show 
that the growth of rope is inhibited as the 
hydrogen ion concentration approaches 10-*N, 
and that bitter flavor in bread appears only at 
greater acidities. 
Professor Wolbach, of the Harvard Medical 
