Marcw# 15, 1901.] 
very remarkable, because, on account of an ac- 
cident in the treatment, a failure or a poor 
positive had been expected. Several repeti- 
tions of this treatment had failed to yield this 
result again. 
It is frequently observed that with a strong 
pyrocatechin developer the picture will start 
asa negative in the light, and will reach a fair 
degree of excellence, and then reverse. This 
is in the nature of an oscillation such as is 
known in electric discharges. The phenome- 
non is not observed in a weaker or in a more 
slowly acting bath. The anomalous case before 
referred to could hardly be accounted for in 
this way, because the picture developed very 
slowly in a normal hydrochinon bath, and grew 
steadily better until it was sharply defined on 
the back of the film. This case is still being 
examined. 
A short biographic sketch of the late Charles 
Pierre Chouteau, a charter member of the 
Academy, who inits early years, as the western 
representative of the American Fur Company, 
contributed many important collections to its 
Museum, was presented by a committee ap- 
pointed for that purpose. 
Two persons were elected to active mem- 
bership. WILLIAM TRELEASE, 
Recording Secretary. 
DISCUSSION AND CORRESPONDENCE. 
A FIELD FOR MOSQUITO THEORISTS. 
CLIMATIC CONDITIONS ON THE UPPER CONGO. 
To THE EDITOR OF SCIENCE :—The following 
extracts from letters of Father Grison, a Mis- 
sionary at Stanley Falls, and Mg’r Roelens, 
Vicaire Apostolique of the Upper Congo, ad- 
dressed to the Société Antiesclavagiste of Bel- 
gium, may be of interest. G. R. 8. 
WASHINGTON, D. C., 
February 12th. 
At Stanley Falls the climate is very agreeable, but 
is formidable, as the victims of fever are too numer- 
ous. Europeans have very inaccurate ideas of trop- 
ical temperatures. I have passed eight years at the 
equator on the Pacific Coast, and have never seen the 
mercury above 29° C. 
Here the maximum is 32° C. and the nights are de- 
liciously cool. This is our climate all the year. 
There is, however, a reverse to this picture. We 
SCIENCE. 
431 
have frequent tempests of indescribable violence ; I 
have counted in one minute during a diluvial rain 
and continuous thunder, sixty-six flashes of lightning ; 
and have seen in two hours within a radius of a few 
hundred meters, ten coup de foudres. 
Mg’r Roelens at M. Pala, writes: 
The work of the Mission allows me little leisure 
for anything else than an occasional attack of fever. 
The fever, however, does not ask if you have the 
leisure, but imposes it at will, and unhappily, a little 
too frequently. 
Dame fever reigns as mistress of the country. 
In the rainy season, from November to May, her 
tyranny is most severely felt ; no one escapes attack ; 
the newly-arrived are most susceptible, but the old 
residents are not completely immune. 
Those who have been resident more than a year 
are the chosen victims of the terrible haematuric fever 
(Malarial hematuric, or ‘Swamp fever.’) In five 
years’ residence I have had the fever fourteen times ! 
For the last two years, fortunately, it has left me in 
peace. 
Brother Stanislas, who has resided here since 1893, 
is now sick with it for the twenty-fifth time. 
It is an old saying here that the third attack is al- 
ways mortal. 
We, however, have passed the period when our 
lives are despaired of ; this result is due to the treat- 
ment we have followed here. 
Since 1892 the missionaries of the Upper Congo 
have applied this treatment to seventy-five cases of 
this fever, of which five only have been fatal. 
Beside this there are no other grave climatic dan- 
gers for Europeans. The dysentery, which elsewhere 
is a serious menace, does not occur: here. 
I suspect that the English at the south of us find 
this malady more frequently in their boxes of con- 
serves, and in la dive bouteille. 
At this moment an epidemic of smallpox is in- 
vading the country. It is said here that this recurs 
every seven years, and attacks all who escaped th 
previous invasion. ; 
We cannot depend upon the vaccine of Europe, 
because of the long voyage and the great heat. 
I have given it many trials without result. 
SHORTER ARTICLES. 
ARE THE AUSTRALIAN MARSUPIALIA OF OPOS- 
SUM DERIVATION. 
AT the last meeting of the American Associa- 
tion for the Advancement of Science, in June, 
1900, the writer presented some reasons in 
