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BAUER. 
presidents that might advantageously have been reviewed 
in connection with our topic. But we lack the time. 
I cannot refrain, however, from quoting once more from 
Henry’s address, already referred to, which I hope you may 
be induced to read in its entirety: 
“Man is a sympathetic being, and no incentive to mental 
exertion is more powerful than that which springs from a 
desire for the approbation of his fellow-men; besides this, 
frequent interchange of ideas and appreciative encourage- 
ment are almost essential to the successful prosecution of 
labors requiring profound thought and continued mental 
exertion.” * * * 
“It is an essential feature of a scientific society that every 
communication presented to it should be subject to free criti- 
cal discussion. Such discussion not only enlivens the pro- 
ceedings, but is generally instructive, frequently elicit- 
ing facts which, though insignificant when isolated, when 
brought together, mutually illustrate each other and lead 
ultimately to important conclusions.” 
Conclusion. 
My address began with statements revealing the necessity 
of keeping our minds ever open and free for the careful 
weighing and the unbiased reception of the facts observed 
and discovered. Throughout I have attempted to lay chief 
stress upon the mental and human elements involved in the 
topic. I cannot do better in closing than to quote you a 
sentence from a letter* which the great mathematical physi- 
cist, James Clerk Maxwell, wrote to Herbert Spencer on a 
subject of controversy in the latter’s “First Principles,” viz.: 
“It is very seldom that any man who tries to form a sys- 
tem can prevent his system from forming around him, and 
closing him in before he is forty. Hence the wisdom of 
putting in some ingredient to check crystallization and keep 
the system in a colloidal condition.” 
Let our watchword therefore he: ever to keep our systems — 
our theories — in a colloidal condition! 
* “Life and Letters of Herbert Spencer, by David Duncan,” vol. n, 
p. 163. 
