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president’s address. 
and render abortive the invasion of tlie more virulent diseases. 
This has lieen attempted by repeated cultivations of the Germs in 
proper media, until after several of such generations the broods shall 
have acquired the requisite diminished vitality, — in fact, until that 
diminution of virulence which the Small Pox Germ has sustained in 
passing through the Cow has been obtained by these artificial means. 
VYe are all familiar with the attempts which have recently been 
made by Pasteur in this direction, in regard to that most fatal 
disease Hydrophobia. It remains to be seen how far he has been 
successful in solving this preventive problem ; and how far this 
may be the true method by which to utilize our knowledge of 
bacterial life. Medical men are diligently working at this subject 
from their own point of view. There is much to be done by 
microscopic naturalists in the unravelling the life-history of these 
little beings ; and we are glad to recognize the kind of results 
which may be hoped for in the future. 
Such considerations as these are fraught with matter for deep 
reflection, and tend to open our minds to the far-reaching 
possibilities not only of this special knowledge, but of that which 
we are gaining in many other branches of science. Each fresh 
item of knowledge is like a new step upon a ladder, and raises us 
to a fresh height from which we can take a wider survey, and 
which we can assume as a loftier and broader basis for further 
enquiry. Scientific thought is ever as to what may ne.xt be done, 
and how to do it. For, as Sir James Paget has recently said : “Every 
increase of knowledge brings before us a larger and clearer view of 
the immeasurable quantity which is still to be gained. The more 
we know, the more can we see, if we will, how much more there is 
that we do not know.” And of this we may be sure, that it is by 
minute and exact work only that in the future our store of knowledge 
is to be increased and made sure. If no other example to prove this 
were at hand, it would be sufficient to quote the recent observations 
of the Pev. Dr. Dallinger on the subject of the conjugation of the 
nuclei of some minute forms of cell life : observations which bring 
us nearer to some definite knowledge of this particular matter than 
any hitherto made upon higher classes of creatures. 
