horse, though
almost any of the domesticated animals will serve the purpose.

But Dr. Roux's paper did not stop with the description of laboratory
methods. It told also of the practical application of the serum to
the treatment of numerous cases of diphtheria in the hospitals of
Paris--applications that had met with a gratifying measure of success.
He made it clear that a means had been found of coping successfully with
what had been one of the most virulent and intractable of the diseases
of childhood. Hence it was not strange that his paper made a sensation
in all circles, medical and lay alike.

Physicians from all over the world flocked to Paris to learn the details
of the open secret, and within a few months the new serum-therapy had
an acknowledged standing with the medical profession everywhere. What it
had accomplished was regarded as but an earnest of what the new
method might accomplish presently when applied to the other infectious
diseases.

Efforts at such applications were immediately begun in numberless
directions--had, indeed, been under way in many a laboratory for some
years before. It is too early yet to speak of the results in detail. But
enough has been done to show that this method also is susceptible of the
widest generalization. It is not easy at the present stage to sift that
which is tentative from that which will be permanent; but so great an
authority as Behring does not hesitate to affirm that today we possess,
in addition to the diphtheria antitoxine, equally specific antitoxines
of tetanus, cholera, typhus fever, pneumonia, and tuberculosis--a set
of diseases which in the aggregate account for a startling proportion
of the general death-rate. Then it is known that Dr. Yersin, with the
collaboration of his former colleagues of the Pasteur Institute, has
developed, and has used with success, an antitoxine from the microbe of
the plague which recently ravaged China.

Dr. Calmette, another graduate of the Pasteur Institute, has extended
the range of the serum-therapy to include the prevention and treatment
of poisoning by venoms, and has developed an antitoxine that has already
given immunity from the lethal effects of snake bites to thousands of
persons in India and Australia.

Just how much of present promise is tentative, just what are the limits
of the methods--these are questions for the future to decide. But, in
any event, there seems little question that the serum treatment will