oe 
TRANSACTIONS OF SECTION D. 531 
proved to be the fact; the potency of certain disease-germs which have been made 
the subject of special research being now found to be capable of a regulation 
almost as precise as the precipitating power of the solution of a chemical re- 
ent, 
2 Notwithstanding the tendency among modern Pathologists to regard the various 
forms of Zymotic disease as specifically distinct, and to attribute to mexact observa- 
tion every recorded fact which runs counter to their preconceptions, the Author 
holds that the application of the natural-history method to the study of these 
diseases fully justifies the belief, that the same germs, undergoing development under 
different conditions, may manifest themselves under a great variety of forms; and 
maintains that a larger study of the history of medicine also justifies the belief that 
while some of these forms (such as the Exanthemata) have acquired a considerable 
fixity, breeding only in the human body, yet that this fixity does not necessarily 
hold good over the whole world, or through all time; and that there is a large 
class, including Cholera and the various forms of Fever, originating in germs which 
breed in the soil as well as in the human body, over which the nature of the breed- 
ing-ground, with various atmospheric (possibly electrical) conditions, exerts a most 
important modifying influence. And he holds that this inclusive study, taking 
account of all the facts which science can bring to bear on the inquiry, is much 
more likely to lead to accurate results, than the exclusive method followed by most 
Pathologists, 
In regard to Cholera in particular, he regarded it as still an open question 
whether this disease is as specifically distinct from all others as it is commonly 
regarded. Though it has been customary to represent true cholera as haying 
always radiated from India (which country never seems entirely free from it), yet 
the author distinctly recollects the occurrence at Clapham of what was recognised 
by an old Indian practitioner as Asiatic cholera, some years before the tirst epidemic 
visitation of 1832. And the report recently made by Surgeon-General Hunter on 
the epidemic of cholera now prevailing in Egypt, attributes its origin to local condi- 
tions, which have produced an increasingly severe type of choleraic diarrhea, at 
last developing true cholera, This entirely accords with the view that disease- 
germs which might originally have only produced a mild form of choleraic disease, 
may be so ‘cultivated’ as to develope its most malignant type. The author illustrated 
this by the example of Small-pox, which he regarded as haying been greatly miti- 
gated during the last century by the beneficial ‘ cultivation’ of its milder variety by 
Inoculation ; while the germs of the same disease, developing themselves during 
the siege of Paris in the blood of men already rendered unhealthy by unfavourable 
conditions, produced a malignant form of the disease, which had never before 
prevailed epidemically during the present century, but which has been during the 
last twelve years the principal source of its fatality. 
7. On Wool Plugs and Sterilised Fluids. 
By J. Duncan Marruews, F.R.S.E. 
The paper described in detail a series of experiments made with the purpose of 
testing how far wool plugs were to be relied on as filters of atmospheric air, and, 
consequently, as preventers of the putrefaction of sterilised Auids protected thereby 
from contamination of germs in the air. 
Flasks containing various cultivating fluids (5 per cent. Liebig’s extract being 
generally employed) were filtered into and boiled in glass flasks of about 4 oz. 
capacity, closed by one or more plugs of cotton wool, or salicylic wool, or wool 
which had been steeped for some time in 5 per cent. carbolic acid and water, and 
often had in addition a sheet of salicylic wool placed over the plug and tied down 
beneath the lip of the flask. The flasks were previously washed out with nitric, 
sulphuric, or carbolic acids, and then with water, and often were subjected there- 
after to a temperature of 400° Fahr. Boiled for fifteen minutes, allowed to cool, 
and then placed in an incubator ata temperature of 100° Fahr., the contained 
fluids—prepared in various laboratories, the air of which was known to be highly 
MM 2 
