from those which surrounded my
generation in the seventies of the last century, when Virchow and
his great contemporaries laid the sure and deep foundations of modern
pathology. Which of you now knows the "Cellular Pathology" as we did? To
many of you it is a closed book,--to many more Virchow may be thought a
spent force. But no, he has only taken his place in a great galaxy. We
do not forget the magnitude of his labors, but a new generation has new
problems--his message was not for you--but that medicine today runs in
larger moulds and turns out finer castings is due to his life and work.
It is one of the values of lectures on the history of medicine to
keep alive the good influences of great men even after their positive
teaching is antiquated. Let no man be so foolish as to think that he has
exhausted any subject for his generation. Virchow was not happy when he
saw the young men pour into the old bottle of cellular pathology the new
wine of bacteriology. Lister could never understand how aseptic surgery
arose out of his work. Ehrlich would not recognize his epoch-making
views on immunity when this generation has finished with them. I believe
it was Hegel who said that progress is a series of negations--the
denial today of what was accepted yesterday, the contradiction by each
generation of some part at least of the philosophy of the last; but all
is not lost, the germ plasm remains, a nucleus of truth to be fertilized
by men often ignorant even of the body from which it has come. Knowledge
evolves, but in such a way that its possessors are never in sure
possession. "It is because science is sure of nothing that it is always
advancing" (Duclaux).

History is the biography of the mind of man, and its educational
value is in direct proportion to the completeness of our study of the
individuals through whom this mind has been manifested. I have tried
to take you back to the beginnings of science, and to trace its gradual
development, which is conditioned by three laws. In the first place,
like a living organism, truth grows, and its gradual evolution may
be traced from the tiny germ to the mature product. Never springing,
Minerva-like, to full stature at once, truth may suffer all the hazards
incident to generation and gestation. Much of history is a record of the
mishaps of truths which have struggled to the birth, only to die or else
to wither in premature decay. Or the germ may be dormant for centuries,
awaiting the