400 
ON T1IE MEDICAL TOPOGRAPHY Ol- SINGAPORE. 
That these germs should ellnde our imperfect observation is not to be 
wondered at when we consider that the dust which floats about con¬ 
tains particles which swell when moistened, and are seen by the mi¬ 
croscope to be the monads of infusoria according to Schultze ; while 
Ehrenberg* has found that the smallest monad of 24,000 an “ 1C ^ 1 
in diameter has a complex stomach and organs of motion in the form 
of cilia. What must be the size of the germs of such monads P But 
though so minute their power of reproduction is wonderful. A sin- 
gle wheel animalcule which was watched for 18 days is capable of a 
four-fold increase in 24 hours, a rate of propagation which would 
afford in 10 days a million of beings. 
Another powerful argument in favor of this vital and parasitical 
principle of malaria is the fact that many of our diseases are so pro¬ 
duced by nature, and have been by artificial means. Dr. Klencke, 
says, he has succeeded in communicating to healthy animals, car- 
ceuoma, tubercle, melanoids, condylomata, warts, oyzena, eoroyza, 
malignant pastule, and hydrophobia by the innoculation of the cells, 
the most rudimentary state of animal existence. Many other di¬ 
seases owe their origin to parasitical animals or vegetables, amongst 
others the various forms of itch and ringworm. The thrush of chil¬ 
dren and the apthce of adults, are according to Dr. Berg of a parasi¬ 
tical growth, and in the sporules of the cells very much resemble those 
of yeast. “ Dr. Berg admits that the parasitic growth may be pro¬ 
pagated in bodies previously unaffected, by sporules floating in the at¬ 
mosphere, particularly under certain electro chemical conditions of the 
air and also of the bodies they effect” (Brit, and For. Med. Rev. No. 
xl.) We have also amongst the lower animals diseases produced by 
contagious parasites, as the muscadine of the silkworm and the vor- 
ticellee growing on the toes of tritons, and causing gangrene. The 
last argument which I shall adduce in favor of the theory is, that 
all chemical agents which are known to destroy animal life, equally 
destroy the active principle of contagion and miasma, such as the 
fumes of acetic acid, chlorine, nitric acid, &c.; sulphur, and its prepa¬ 
rations, as sulphurous acid, are powerful antiseptics, and are used to 
avert the decay of woody fibre. On the contrary, whatever tends to 
