en will not develop
diphtheria unless they have been exposed to the contagion, while, if
they should be, we have a remedy against it.

He was a bold man who first ventured to announce this, and for years the
battle raged hotly. It was early admitted that certain cases of
so-called membranous croup in children occurred after or while other
members of the family or household had diphtheria; and for a time the
opposing camps used such words as "sporadic" or scattered croup, which
was supposed to come of itself, and "epidemic" or contagious croup,
which was diphtheria. Now, however, these distinctions are swept away,
and boards of health require isolation and quarantine against croup
exactly as against any other form of diphtheria.

Cases of fatal croup still occasionally occur which cannot be directly
traced to other cases of diphtheria, but the vast majority of them are
clearly traceable to infection, usually from some case in another child,
which was so mild that it was not recognized as diphtheria until the
baby became "croupy" and search was made through the family throats for
the bacilli.

For years we were in doubt as to the cause of diphtheria. Half a dozen
different theories were advanced, bad sewerage, foul air, overcrowding;
but it was not until shortly after the Columbus-like discovery, by
Robert Koch, of the new continent of bacteriology, that the germ which
caused it was arrested, tried, and found guilty, and our real knowledge
of and control over the disease began. This was in 1883, when the
bacteriologist Klebs discovered the organism, followed a few months
later (in 1884) by Loeffler, who made valuable additions to our knowledge
of it; so that it has ever since been known as the Klebs-Loeffler
bacillus. This put us upon solid ground, and our progress was both sure
and rapid: in ten years our knowledge of the causation, the method of
spread, the mode of assault upon the body-fortress, and last, but not
least, the cure, stood out clear cut as a die, a model and a prophecy of
what may be hoped for in most other contagious diseases.

Great as is the credit to which bacteriologists are entitled for this
splendid piece of scientific progress, there was another co-laborer, a
silent partner, with them in all this triumph, an unsung hero and martyr
of science who deserves his meed of praise--the tiny guinea-pig. He well
deserves his niche in the temple of fame; and as other races and ages
have worshiped the elep