1 - The Development of the Germ Theory of Infectious Diseases

Abstract

This chapter discusses the development of the germ theory of infectious diseases. In 1840, an important paper was published by a 31-year-old Jacob Henle, like Schoenlein, of Zürich. In that paper, Henle reviews the origin of infectious diseases. He insisted on the specific differences between different diseases in this group and considered that it must, therefore, follow that there were specific differences between their causes. He then adduced evidence that the causes of infectious diseases were living agents that stood in the relation of a parasitic organism to the diseased body. During the 1840s, bacteria and fungi were found in sputum, discharging ears, stomach contents, etc., of man in association with various diseases, and the theory that fungi were the cause of many infectious diseases received wide credence. However, the critical assessment of such claims advocated by Henle was ignored. His paper seems to have been relatively soon forgotten for an active worker and protagonist of the germ theory, J. B. Sanderson, only came across it by chance in the year 1875. Sanderson, although he had spent many years in the experimental study of bacteria in relation to disease and was probably Britain's foremost exponent of the germ theory, made a very lame reply to these apparently cogent arguments.