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I 
18 THE NORTHERN MICROSCOPIST. 

elaborate accessories or of the finest high power objectives. He touched on 
the pleasure which microscopists experienced in following out their investiga- 
tions, warned them that the management of the light was of the first importance, 
and dwelt at some length on the various objectives of more or less power. ‘‘I 
cannot conclude,” said the President, ‘‘ without alluding briefly to certain 
remarkable results which have followed from investigations made by means of 
the microscope into the producing cause of some intractable diseases. It 
has been long known that germs which produce disease of various character 
are continually floating in the air in inconceivable profusion, and that on falling 
on tissue in a suitable state to nourish them they grow and produce the disease 
in question. It has only been within the last few years, however, and in some 
cases within the last few months, that the germs of some of the most fatal 
diseases which attack animals and man have been detected by the microscope 
in tissue or in the blood, and not only detected but isolated, and not only 
isolated but cultivated, and not only cultivated but so attenuated and deprived 
of their virulence that inocculation with them could be safely resorted to, and 
the subject be thus practically rendered proof against the terrible disease in its 
most malignant form, even though exposed to its most baneful influence. I 
refer, of course, to the researches of M. Pasteur, Dr. Koch, Dr. Klein, M. 
Toussaint, and other distinguished physicians and veterinary surgeons. The 
experiments hitherto made by these observers have been chiefly but by no means 
exclusively confined to the diseases of animals. The first success was attained 
by M. Pasteur in his attempt to arrest the progress of the silk-worm disease. 
The germs of this disease were discovered. Infected insects or eggs were 
separated from those which were not infected, and such successful methods 
suggested for stamping out the disease that they were recognised both by his 
own and foreign governments. Afterwards his attention, and that of other 
workers in the same field, was turned to other diseases. The very fatal splenic 
fever of sheep and cattle, identified by continental writers with the murrain of 
Egypt, the pig-typhoid, the fowl-cholera, the cattle disease known as Za maladie 
de chaberd, and even hydrophobia, have been the subject of careful experiment. 
In each of them a microscopic organism, a bacterium or a bacillus, less than the 
thousanth part of an inch in length, has been found in the blood, and discovered 
to be the cause of the disease. The organism has been separated, cultivated in 
chicken soup, made almost innocuous by long exposure to the oxygen of the 
atmosphere, and then used for inoculation purposes. After this it is found that 
though the constitutional disturbance set up has been very slight, the animals so 
inoculated are almost if not quite proof against the disease, even though the 
germs of it in their virulent form have been introduced into the blood. In the 
case of diseases of other kinds, which attack the human subject—such as ague, 
malarial fever, and that rapid and fatal form of it, yellow fever—similar 
organisms have been found in the blood, and the treatment of the diseases by 
the injection into the veins of phenic acid, which is known to destroy such germs, 
has been attended with success. That like causes may be traced, and some 
kindred treatment successfully adopted, in the case of other epidemic or conta- 
gious maladies, seems to be highly probable ; and as the result of this new 
microscopic departure in regard to the theory and the treatment of disease, it is 
hoped that there may in due time be a large abatement in the death-roll 
attributable to such widespread and dangerous disorders as scarlet and typhus 
fever. Such investigations as these can, of course, only be carried out by those 
trained in medical science. But there is abundance of work for others to do in 
the examination of those most interesting animal and vegetable organisms with 
which our ponds and rivers and hedge banks teem. What we want is to enter 
into the matter with spirit, and with unflagging interest. We have already in 
our Society a fair number of members who wish to avail themselves of the 
advantages it affords. Most of them are workers in the field of microscopical 
investigation, and I should hope that none of those who belong to the Society 

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