262 
and the state colleges cooperating with it 
quickly took steps to expand the extension 
work, with a view to placing in each rural 
county one or more agents. Within a year 
the number of county and home demonstration 
agents, club leaders and specialists in various 
lines employed in the great extension system 
was more than doubled, thus putting into effect 
within a year a program of expansion which 
under ordinary conditions would have re- 
quired many years to complete. 
The number of men county agents has been 
increased from 1,434 to 2,485 within the 
year, the women home demonstration agents’ 
from 537 to 1,715, and similar increases were 
made in the personnel of the boys’ and girls’ 
elub work. To-day there are employed in 
this great educational system over 6,000 
county and home demonstration agents, club 
‘leaders, and specialists in various lines, and 
the extension work is organized in substan- 
_ tially every agriculturally important county 
in the country. These agents are not only 
aiding the farmers in agricultural problems, 
but they are also rendering valuable assistance 
to other branches of the government, such as 
the Treasury Department, the Food Adminis- 
tration, and the Red Cross, in the prosecution 
of their war activities. 
The efforts and achievements of the millions 
of farm men and women of America have been 
noble and remarkable. The farmers have oc- 
eupied the first-line trenches of the food army. 
They and the agencies assisting them, the 
Federal Department, the state colleges, and 
also the state departments of agriculture, were 
ready when a state of war was declared and 
had been for years. They were charged with 
the responsibility for maintaining and in- 
creasing production. How they haye dis- 
charged their task the results of last year’s 
production operations and of this year elo- 
quently testify. Davw F. Houston, 
Secretary of Agriculture 
SCIENTIFIC EVENTS 
TRENCH FEVER AND LICE! 
In October, 1917, the American Red Cross 
Society, in conjunction with representatives 
1¥From Nature. 
SCIENCE 
[N. S. Von. XLVITI. No. 1237 
of the British Expeditionary Force, formed a 
committee to investigate trench fever. This 
body has carried out much very valuable work, 
but its full report has not yet been made. 
About the same time a War Office Commit- 
tee, under the chairmanship of Major-General 
Sir David Bruce, was formed in England, in 
order to advance the knowledge of trench fever 
with a view to its prevention, and the research 
in progress at Hampstead was merged in that 
of the committee, of which Major Byam be- 
came a member. 
Up to the close of the year the work was con- 
fined to the study of clinical evidence, the ex- 
amination of the blood and urine of patients, 
together with the feeding of lice on them dur- 
ing their febrile periods, followed by the sub- 
sequent microscopical examination of the in- 
sects with a view to the discovery of the 
infecting organism. 
With the commencement of 1918, thanks to 
the financial assistance of the Lister Institute 
and the courageous and patriotic action of a 
number of volunteers, it became possible to 
widen the scope of the research, and very valu- 
able results speedily followed. A confirmation 
was obtained of McNee’s main results of di- 
rect inoculation from patient to patient by 
blood, and the problem of transmission by the 
louse was seriously attacked. The committee 
was fortunate in having at its disposal ample 
stocks of lice, free from suspicion of previous 
infection, which had been reared under the di- 
rect supervision of Mr. Bacot, entomologist to 
the Lister Institute. 
The first experiments in which the insect 
vector was concerned consisted in two of the 
volunteers submitting themselves to the bites 
of several hundred lice daily, the insects hay- 
ing been previously fed on patients during 
febrile periods both before and during the 
month of experiment. The lice, therefore, had 
many opportunities of becoming infected, and 
the men received the bites of these lice three 
times each day for thirty days. Neither 
showed any of the symptoms of trench fever. 
Next, following the analogies of relapsing 
and typhus fevers, two volunteers were inocu- 
lated from lice which had fed repeatedly on 
trench-fever patients. In both the inoculation 
