MarcH 17, 1904] 
WATORE 
467 
-of its second host—a file-fish (Balistes). If the life- 
history is to be completed, the file-fish must in turn 
be swallowed by one of the large elasmobranchs, 
within the body of which the final adult stage is 
reached, and from thence escape the free-swimming 
embryos to renew the cycle. 
where all runs smoothly—for the parasite—no pearls 
are formed. On the other hand, when the oyster 
escapes the file-fish, the larval parasite, unable to com- 
plete its development, dies, and becomes encapsuled 
by the pearly nacre deposited by the living tissues of 
the oyster upon the source of irritation. 
Throughout his report Prof. Herdman bestows un- 
stinted praise on the work of his assistant, Mr. 
Hornell, and there can be no doubt but that it is most 
thoroughly deserved, for much work of the highest 
importance was entrusted to him, and he in every 
case proved worthy of the trust. We are therefore 
glad that Prof. Herdman’s wish has been fulfilled— 
Fic. 2.—Valuation sample of pear] oysters from the Cheval Paar, being brought 
on board the Nangasameeforawee from the inspection boats. 
photograph by J. Hornell. 
that Mr. Hornell should be asked to continue his ob- 
servations as marine biologist at the Galle Laboratory 
—for he will now be able to render ‘‘ signal service 
to the pearl, sponge, trepang and other marine 
fisheries of the Colony.”’ 
In concluding this notice we must not omit to 
mention that a series of separate reports has been 
prepared by various specialists on material collected 
during this investigation. 
included in the present volume, and others are to 
follow. The first of these deals with the geology of 
the sea-bottom, and describes the formation of the 
peculiar bottom essential to the presence and well- 
being of the pearl oyster. Mrs. Gepp, in an account 
of the algze collected, describes the hitherto unknown 
fructification of a species of Halimeda. 
The remaining reports are zoological, and describe 
the Gephyrea, Chitons, Holothurians, Cephalochorda, 
and Copepoda. Mr. Tatersall’s report on Amphioxus 
NO. 1794, VOL. 69] 
Seven of these reports are | 
In these cases, however, | 
From a 
will be read with great interest. No less than seven 
of the eleven species known occur around Ceylon. 
““The tables at the end of the report show how ex- 
tremely variable the species of the group are, and the 
more extended our knowledge of this group becomes 
the less do the species appear to be separated.’? The 
report on the Copepoda, by Messrs. Thomson and 
Scott, is by far the largest of these supplementary re- 
ports, and embraces descriptions of no less than 283 
species, of which 76 are new to science. 
Further. description of this most valuable book we 
cannot give. It must be read to be appreciated. The 
vast wealth of information contained in Prof. Herd- 
man’s report on the pearl oyster alone demanded far 
more space than we have been enabled to afford it. 
Enough, however, has probably been said to show that 
the commission was not only completely justified, but 
has resulted in a rich harvest of facts which appeal 
not merely to those interested in the pearl fisheries or 
to students of mollusca, but to the biologist the 
world over. 
The volume is well bound, well printed, and 
profusely illustrated. Wee been 
THE CAMPAIGN AGAINST MALARIA. 
opts unhealthiness of many tropical countries 
is largely due to the prevalence of malarial 
diseases. The discovery that a particular kind 
of mosquito is the definitive host of the malaria 
parasite paved the way for a method of preven- 
tion based upon the destruction of the malaria- 
bearing mosquitoes, which, so far as present 
knowledge all belong to the genus 
Anopheles. At first the measures of prevention 
were individual rather than general, and in- 
cluded the destruction of mosquitoes in and 
about the house, and their exclusion by nets and 
wire gauze. But through the labours of Major 
Ronald Ross on the west coast of Africa, and of 
the Americans in Cuba and elsewhere, it has 
been shown that much may be done to free a 
whole town from mosquitoes, thereby diminish- 
ing the incidence of malaria. 
The report under review details the measures 
initiated in India by the members of the Royal 
Society’s Malaria Commission to test the efficacy 
of mosquito destruction in the prevention of 
malaria. The station selected was Mian-Mir, a 
cantonment near Lahore, the garrison of which 
consists of about 3900 officers and men, British 
and native, and of 600 native followers. Situated 
in a plain with an average rainfall of about 20 
inches, little of the surface water can drain 
away, especially as the subsoil is exceedingly 
impervious, so that after one or two hours’ rain 
the locality becomes flooded. In addition there are 
numerous brick-work surface drains, which become 
filled and form excellent breeding-places for the Ano- 
pheles until dried up by the sun. Owing to these con- 
ditions, Mian-Mir is one of the most unhealthy canton- 
ments in India, the mean annual admission rate for 
ague among European troops averaging 663 per 1000. 
Six species of Anopheles were found to be present, of 
which A. Rossii was the most abundant, the numbers 
reaching a maximum in September and October. 
The methods of prevention adopted were (1) the 
cleaning of irrigation water courses, smoothing their 
sides, and where possible lining with brick and cement; 
(2) drying out and cleaning branch water courses every 
ten days; (3) treatment of water courses with kerosene 
oil; (4) draining small collections of stagnant water; 
goes, 
1 ‘The First Report of the Anti-malarial Operations at Mian-Mir, 1901- 
1903.” By Capt. S. P. James, I.M.S. (Scientific Memoirs of the 
Government of India, No. 6. Calcutta, 1903.) 
