the "bacillus tuberculosis" (1882) is, in its far-reaching
results, one of the most momentous discoveries ever made.

Of almost equal value have been the researches upon the protozoan forms
of animal life, as causes of disease. As early as 1873, spirilla were
demonstrated in relapsing fever. Laveran proved the association of
haematozoa with malaria in 1880. In the same year, Griffith Evans
discovered trypanosomes in a disease of horses and cattle in India, and
the same type of parasite was found in the sleeping sickness. Amoebae
were demonstrated in one form of dysentery, and in other tropical
diseases protozoa were discovered, so that we were really prepared for
the announcement in 1905, by Schaudinn, of the discovery of a protozoan
parasite in syphilis. Just fifty years had passed since Pasteur had
sent in his paper on "Lactic Acid Fermentation" to the Lille Scientific
Society--half a century in which more had been done to determine the
true nature of disease than in all the time that had passed since
Hippocrates. Celsus makes the oft-quoted remark that to determine
the cause of a disease often leads to the remedy,(*) and it is the
possibility of removing the cause that gives such importance to the new
researches on disease.

(*) "Et causae quoque estimatio saepe morbum solvit," Celsus,
Lib. I, Prefatio.--Ed.

INTERNAL SECRETIONS

ONE of the greatest contributions of the nineteenth century to
scientific medicine was the discovery of the internal secretions of
organs. The basic work on the subject was done by Claude Bernard, a
pupil of the great Magendie, whose saying it is well to remember--"When
entering a laboratory one should leave theories in the cloakroom." More
than any other man of his generation, Claude Bernard appreciated the
importance of experiment in practical medicine. For him the experimental
physician was the physician of the future--a view well borne out by the
influence his epoch-making work has had on the treatment of disease. His
studies on the glycogenic functions of the liver opened the way for the
modern fruitful researches on the internal secretions of the various
glands. About the same time that Bernard was developing the laboratory
side of the problem, Addison, a physician to Guy's Hospital, in 1855,
pointed out the relation of a remarkable group of symptoms to disease
of the suprarenal glands, small bodies situated above the kidneys, the
importance of which had not been