550 Analyses of Books. [September, 
&c. Paris green (copper arsenite) and London purple (an 
arsenical residue from the manufacture of magenta) are effectual, 
but they are too dangerous to sprinkle over cabbages. 
If we take this section in connection with that on epizootics 
due to minute living organisms, it must strike the most careless 
observer to what an extent the supply of human food, and hence 
the possible quantity of human life is limited by minute animals 
and plants. We cannot help thinking that the war against 
“ poverty ” can be more successfully waged by the biologist and 
the chemist than by socialistic agitators. 
Bulletin of the Philosophical Society of Washington. Vol. VI. 
Containing the Minutes of the Society for the Year 1883, 
and the Minutes of the Mathematical Section from its 
Organisation, March 29th, to the close of the year. Pub- 
lished by the Co-operation of the Smithsonian Institution. 
Washington : 1884. 
Among the most noteworthy papers here included is one by Mr. 
F. A. King on “ The Prevention of Malarial Diseases, illustrating 
the Conservative Function of Ague.” The author contends— 
and with a great show of ' probability — that the principal faCts 
concerning the occurrence of marsh-fevers are best explained by 
the theory that these diseases are due to the bites of mosquitoes 
and other man-haunting suCtorial insedts. That the Diptera are 
the great colporteurs of infectious disease has been our opinion 
for thirty years, and until lately it has been simply — very simply 
— derided. Now the tide is turning. There are, however, some 
points on which we cannot, all at once, agree with Mr. King. 
He considers that the dark hue of the negro’s skin is protective : 
— “ The negro is protected from the sight, and consequently from 
the bite, of the mosquito ; a similar protection being further 
secured by the offensive odour and greasiness of his cutaneous 
secretions, aided by artificial inunCtion of the body with grease, 
paint, and pitch.” He considers malarial melanosis to be the 
<< designed natural termination of ague, — its conservative function 
destined to modify the individual by defensive adaptation 
against the mosquito.” 
We do not know in how far the negro may escape the sight of 
mosquitoes rather than does the Aryan. Nor can we say which 
of the two is most agreeable to mosquito olfactories. But we 
find something strange in the author’s reasoning. Ague is pro- 
duced by mosquito bites, and its ultimate result is to render man 
less susceptible to such bites ! Surely, if Nature’s objeCt had 
been the protection of man, it might have been reached by a 
simpler and more effective process. We would also ask how it 
is that mosquitoes are prevalent in Lapland, the north coast of 
