676 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
The great Frenchman, Pasteur, in making a thorough examination 
of the process by which alcohol was obtained from sugar, discovered 
the part played by the organism known as yeast, and established the 
idea of organized ferment bodies. He extended his observations to 
other micro-organisms, and, in conjunction with his coworkers, 
among whom must be included those who were looking into the 
question of the spontaneous generation of living matter, definitely 
gave us the idea that putrefaction was caused by micro-organisms 
acting upon organic matter, that these micro-organisms are capable 
of resisting drought, and when dried float freely in the air and are 
distributed everywhere. When they fall upon a suitable material, 
their vital activity is resumed, and they increase with incredible 
rapidly and set up putrefaction. It was reserved for our distin- 
guished countryman, Lister, then a surgeon in Edinburgh, to recog- 
nize the importance of these discoveries for surgery. Knowing of 
the researches of Pasteur and his fellow-workers, he conceived the 
-idea that suppuration was due to putrefaction in the organic matter 
of the wounds caused by micro-organisms. Acting on this, he intro- 
duced his method of antiseptic surgery, by which his name has been 
rendered immortal. I think we may say that no single application 
of the results of pure research has done more to preserve human life 
and to diminish human suffering than this linking up by Lister of 
the putrefaction of suppuration with the work of his predecessors 
on the effects of the actions of micro-organisms upon organic matter. 
It is well to notice, in passing, that this discovery of Lord Lister’s is 
a good illustration of the difficulty which the human mind has of 
conceiving even the simplest new idea. To us, now, how simple 
seems the step which Lister made; yet there were thousands of sur- 
geons in the world who failed to make it, though they were continu- 
ally dealing with suppurating wounds and wondering why they 
suppurated, and when it was-made it was stoutly discredited by many 
quite able men. 
T must now turn to another subject which is closely connected with 
the preceding, and well illustrates my thesis that pure scientific re- 
search, without reference to practical utility, is of the highest im- 
portance to mankind. 
Tt will doubtless have occurred to many of you to ask the question, 
How is it, if the air contains floating in it the dried spores of multi- 
tudinous micro-organisms which only need a suitable medium for 
their development and increase, how is it that they do not obtain a 
lodgment in the healthy animal body, which one would think offers 
all the conditions necessary to their growth? It can easily be shown 
that the air we breathe, the water we drink, the food we eat, every- 
thing that we touch, swarms with these microscopic creatures; that 
they enter our lungs, that they germinate in our skin, that they occur 
