course are not excluded for the present. But we may assume that
these will be removed as easily and quickly as the first attack.

On the other hand it is possible from analogy with other
infectious diseases that those who are once cured become
permanently exempt. This must also be considered an open
question for the present.

[4] It was impossible to collect data referring to
cerebral-laryngeal-and miliary-tuberculosis, as we did not have
sufficient material.

Explanatory Notes.

Koch states that he can not at the present make any statement about the
origin and preparation of the remedy, as his labors are not yet
completed.

We may assume that it is very probably a substance that corresponds in a
way to the lymph used for vaccination. As vaccine lymph represents
variolous poison greatly reduced in strength, as the remedy for
hydrophobia is composed of a substance which is weakened hydrophobic
poison, so Koch probably obtains his remedy for tuberculosis by
artificially reducing the tuberculous poison by means of various
processes.

A number of years ago it has been tried with syphilis in a similar way
to obtain a substance that would not only cure syphilis but would also
guard against infection from it. At that time however the experiment was
not successful.

From several intimations I am inclined to believe that Koch was
successful in finding a way in which a substance may be produced for
contagious diseases, a substance that cures these diseases and also
protects from infection. It is not impossible, since Jenner found the
vaccine virus, Pasteur the hydrophobic lymph and now Koch the tubercle
lymph.

To be sure there is this difference for the present between the
substances named, that the vaccine virus only protects healthy person
from infection by small pox but it does not cure those sick, while the
hydrophobic lymph and tubercle lymph cure the afflicted. However Koch
seems to believe that his tubercle lymph has a certain power of
producing immunity.

According to Koch, his remedy, consisting of a brownish liquid, is
easily perishable as soon as it is diluted with water; he recommends the
preparation of the dilution of the remedy with a 5 per cent. phenol
solution. Phenol is equivalent to carbolic acid. The dilution of the
remedy for use must be considerable, as only small quantities of the
same are used.

Koch tells us that his remedy does not act through th