148 
sible. The caprylates, which are the first in 
the series to show distinct hydrophilic proper- 
ties, are good emulsifying agents, and, gen- 
erally speaking, the value of these emulsifying 
agents increases steadily as we mount in the 
fatty acid series. An upper optimum is shown 
by those soaps which (like sodium stearate) 
are brittle and “dry” at ordinary tempera- 
tures. But the potassium soaps of these 
higher fatty acids are all good emulsifiers as 
are even the sodium soaps if the temperature 
is increased whereby the brittle, crystalline, 
colloid hydrates formed at lower temperatures 
are converted into more tenacious colloids 
which bear stretching into thin layers without 
rupture. 
How important is the degree of hydration of 
the soap for thus stabilizing the emulsions is 
also well shown when the effects are studied 
of adding an alkaline salt in progressively 
higher concentrations to one of the more liquid 
soaps (like sodium oleate, sodium caprylate, 
sodium laurate or potassium palmitate, mar- 
garate, or stearate). As previously noted, the 
hydration capacity of the soaps is increased 
at first, decreased later and finally reduced to 
zero. Similarly the emulsifying power of the 
soap at first increases then decreases and 
finally becomes zero. 
Martin H. Fiscurr, 
Marian O. Hooxer 
Ercubure LABORATORY OF PHYSIOLOGY, 
UNIVERSITY OF CINCINNATI, 
June 15, 1918 
FIELD CONFERENCE OF CEREAL 
PATHOLOGISTS A 
THE fourth Annual Conference of Cereal Pathol- 
ogists was held at Purdue University, Lafayette, 
Ind., beginning June 19 and ending Friday after- 
noon, June 21. Forty names were signed to the 
Tegister. A tentative program was presented 
as a guide for discussion, although no formal pro- 
gram had been prepared in advance. This fact 
helped to make the meetings more informal and all 
discussions were in the nature of round-table talks. 
Certain members were asked to lead in the discus- 
sion upon topics in which they were especially in- 
terested. 
SCIENCE 
[N. S. Von. XLVIII. No. 1232 
8:30 A.M., June 19—24 Present. 
Professor H. P. Barss called the conference to 
order and after a few introductory remarks the 
program was taken up. 
Barberry Eradication—Dr. Stakman reported 
upon progress of the work of barberry eradication. 
Among other things he brought out the fact that 
barberries were much more numerous and more 
widely distributed than had been supposed, that 
they were quite universally rusted even on well- 
kept lawns, that in the northern United States, all 
eases of early infection of stem rust upon grains 
and grasses had been directly traceable to bar- 
berries and that the barberry campaign was suc- 
ceeding in rapidly clearing the states from Ohio 
to Montana and from Missouri to Canada of this 
worthless shrub. He said that reports had come 
in indicating that 70 to 90 per cent. of the bushes 
were already out in North Dakota, South Dakota, 
Minnesota, Wisconsin, Iowa, Michigan, Nebraska 
and northern Illinois. The fact was also brought 
out that the common barberry has escaped from 
cultivation in some few places. 
Dr. A. G. Johnson reported finding a hybrid of 
the common barberry which was infected. He em- 
phasized three points: (1) Barberries spring up 
from the roots when dug up, if the work is not 
thoroughly done; (2) seedlings of barberries had 
been found badly infected; (3) barberries had 
been located in many obscure places. Mr. Dixon, 
of Wisconsin, reported on some work upon over- 
wintering of uredinia, He found no overwintering 
of uredinia in 125 stations visited every two weeks 
during winter and spring. Dr. Stakman stated 
that this had also been the experience of various 
other field scouts both this year and last. 
Dr. Coons reported good progress in Michigan 
and stated that the strong arm of the law was 
needed to complete the work. All barberries had 
been removed which could be removed by publicity 
work. He also stated that no stem rust had been 
observed until after infection had become common 
upon barberries. 
Professor Selby reported good progress from 
Ohio. He stated that the attitude of the people 
in general was to wait for infection. 
Professor Jackson stated that the scouting work 
in Indiana had been confined to the northern part 
of the state. 
Dr. Stevens and Dr. Anderson were both present 
from Illinois. They stated that infection was 
abundant in Illinois in the northern part, and 
down the Mississippi River as far as Rock Island. 
Stem Rust Studies.—Dr. Stakman reported very 
