318 
quently the disinfection of clothing and houses 
is useless. The fever can be produced by a 
subcutaneous injection of blood from a patient 
who must have had the disease for not more 
than two days. Mosquitoes must also bite the 
patient during the first two days of his illness 
or they cannot transmit the disease. The board 
kept an infected mosquito for fifty-one days, 
when it was allowed to bite a person who 
contracted the disease. The board differs from 
Dr. Finlay in that the latter holds that more 
than one kind of mosquito can convey yellow 
fever. The board says there is only one kind 
that can do so. Dr. Finlay also says that a mos- 
quito can transmit the disease the fourth or fifth 
day after biting a patient, while the board says 
that twelve days must intervene. The board 
reported that non-immunes were allowed to 
sleep in infected clothing and bedding, but 
none contracted the disease. A member of the 
Congress objected that these so-called non 
immunes might really have been immunes. 
The board replied that two of these were sub- 
sequently subjected to the bites of infected 
mosquitoes and contracted the disease. The 
moral aspect of the experiments was touched 
It was pointed out that members of the 
board were themselves bitten and one of them 
died. Yellow fever is not due to dirt. It may 
occur in the cleanest localities. Dr. Wilde of 
the Argentine Republic proposed the creation 
of an international yellow fever board to study 
means of exterminating the disease. 
upon. 
THE Illinois Society of Engineers and Sur- 
veyors held its sixteenth annual meeting at 
Bloomington on January 23d—25th. 
AT a meeting in San Francisco a committee 
of fifteen was authorized for the preparation of 
plans for a Pacific Coast Medical Association. 
A CONFERENCE of science masters in public 
schools was held recently in the rooms of the 
University of London, at South Kensington, 
with Sir Henry Roscoe in the chair and about 
fifty members in attendance. The subjects 
discussed included the order of science teaching, 
the coordination of the teaching of science and: 
mathematics, natural history societies, aud sci- 
ence and examinations. 
The Couneil of the St. Louis Academy of 
SCIENCE. 
[N.S. Von. XIII. No. 321. 
Science announces that it has arranged for a 
series of addresses on the progress made in the 
several departments of pure and applied science 
during the nineteenth century. These ad- 
dresses, to which the public is welcome, are 
given at the Academy Rooms, 1600 Locust 
street, at the second stated meeting of each 
month, at 8P. M. Subject to revision due to 
unforeseen causes, the following program is an- 
nounced for these meetings: 
January 21st, Rev. M. S. Brennan, ‘ Astronony.’ 
February 18th, Professor J. L. Van Ornum, ‘ Engi- 
neering.’ 
March 18th, Dr. E. H. Keiser, ‘Chemistry.’ 
April 15th, Mr. C. F. Marbut, ‘ Geology.’ 
May 20th, Professor George Lefevre, ‘ Zoology.’ 
October 21st, Professor F. E. Nipher, ‘ Physics.’ 
November 18th, Mr. Herbert F. Roberts, * Botany.’ 
December 16th, Mr. F. Louis Soldan, ‘ Education.’ 
THE public lectures under the auspices of the 
department of zoology of Columbia University 
are being given this year by Dr. Gary N. Cal- 
kins, the dates and titles being : 
February 15—‘ The Simplest of Living Animals. 
General Sketch.’ 
February 19—‘ The Sarcode Animals ; Naked bits 
of Protoplasm.’ 
February 26—‘ The Flagellated Organisms, the Most 
Important Group, theoretically, of the Protozoa.’ 
March 1—‘The Malarial Germ and other Sporozoa.’ 
March 5—‘ Infusoria, the Highest Type of Protozoa.’ 
March 8—‘ The Loss of Vitality in Protozoa and 
its Renewal through Conjugation.’ 
March 12—‘ The Protozoon, a Physiological Ma- 
chine.’ 
PROFESSOR NIPHER, of Washington Univer- 
sity, is still making progress in his photographic 
work. If his pictures are unsatisfactory on first 
development, he destroys the picture chemically 
and starts again with a clean film. 
ture is 
and is 
picture 
picture 
picture 
If the pic- 
started as a negative in the dark room 
unsatisfactory, he first dissolves the 
with the fog on the plate, then a fresh 
is developed on the same film. This 
may be a negative in the dark room, or 
it may be a positive, if the development takes 
place in the light. In asimilar way, if the first © 
picture is a positive, the second picture may 
be either a positive or a negative, according as 
the second development is in the light or in the 
dark room. Thereisa great advantage in start- 
