The Herter Lectures. I. Spirochaetosis. Lecture delivered on the Herter Foundation, Johns Hopkins University, Baltimore, Maryland, U.S.A., 8 October, 1912

Under the term “Spirochaetosis” are included those diseases of man and animals due to the spiral microorganisms known as spirochaetes. I shall confine myself to those which produce blood infection—the relapsing fevers—in which a remarkable periodic increase and decrease in the number of the spirochaetes is observable corresponding to alternating rises and falls of the host's body-temperature. Authority is divided as to whether the spirochaetes are Protozoa or Bacteria, and the matter is a fruitful theme of discussion upon which I shall not enter here. Judged, however, from their pathological effects and their prompt reactions to immune sera and certain drugs, they show a pronounced affinity to Protozoa and exhibit phenomena not hitherto observed in Bacteria.