ar mode of
infection, whether it be by the atmosphere the physician carries about
him into the sick-chamber, or by the direct application of the virus to
the absorbing surfaces with which his hand comes in contact. Many facts
and opinions are in favor of each of these modes of transmission. But it
is obvious that in the majority of cases it must be impossible to decide
by which of these channels the disease is conveyed, from the nature of
the intercourse between the physician and the patient.

3. It is not pretended that the contagion of puerperal fever must always
be followed by the disease. It is true of all contagious diseases, that
they frequently spare those who appear to be fully submitted to their
influence. Even the vaccine virus, fresh from the subject, fails every
day to produce its legitimate effect, though every precaution is taken
to insure its action. This is still more remarkably the case with
scarlet fever and some other diseases.

4. It is granted that the disease may be produced and variously modified
by many causes besides contagion, and more especially by epidemic and
endemic influences. But this is not peculiar to the disease in question.
There is no doubt that small-pox is propagated to a great extent by
contagion, yet it goes through the same periods of periodical increase
and diminution which have been remarked in puerperal fever. If the
question is asked how we are to reconcile the great variations in the
mortality of puerperal fever in different seasons and places with the
supposition of contagion, I will answer it by another question from
Mr. Farr's letter to the Registrar-General. He makes the statement that
"five die weekly of small-pox in the metropolis when the disease is not
epidemic,"--and adds, "The problem for solution is,--Why do the five
deaths become 10, 15, 20, 31, 58, 88, weekly, and then progressively
fall through the same measured steps?"

5. I take it for granted, that if it can be shown that great numbers
of lives have been and are sacrificed to ignorance or blindness on this
point, no other error of which physicians or nurses may be occasionally
suspected will be alleged in palliation of this; but that whenever and
wherever they can be shown to carry disease and death instead of health
and safety, the common instincts of humanity will silence every attempt
to explain away their responsibility.

The treatise of Dr. Gordon of Aberdeen was published in the year 1795,
being a