Pilots

PILOTS, see Aviation Hygiene. LOEFFLER, Friedrich (Friedrich Loeffler, 1852-1915), one of the founders of medical microbiology. Soon after graduating from the university (1879), he entered the hygienic laboratory of Wolffhügel at the Imperial Health Office (Gesundheitsamt) in Berlin. Already a year later, with the arrival of Robert Koch at this institution, Loeffler became his first student, collaborator, and close friend. In 1888, Loeffler moved to Greifswald to the chair of hygiene, which he left only in 1913 to head the Koch Institute. The world significance of

Loeffler is based on his discovery of the causative agent of diphtheria (1884; simultaneously with Klebs), which made it possible for Roux, Behring, and others to develop methods of active and passive immunization against this disease. The discovery by

Loeffler of the causative agent of glanders

(1882) provided veterinary science with a firm basis for combating this disease and for diagnosing it even in a latent form using 'mallein' discovered by C. I. Helman. Working on foot-and-mouth disease, Loeffler was the first to discover an ultramicroscopic pathogenic agent—the so-called filterable virus (see Virus)—thus opening a vast new field for scientific and practical research. Working on swine erysipelas, Loeffler shed light on the etiology of a number of diseases in this species of animals. An accidental laboratory observation by Loeffler contributed (1891) to the discovery of the mouse typhoid bacillus, with the help of which he managed already the following year to save a large part of the harvest in Thessaly, which was threatened with complete destruction by field mice. Another contribution of Loeffler pertains to bacteriological technique and methodology: staining of microbes and their flagella, new nutrient media, especially elective ones. Among the large number of works published by Loeffler, the most important are: «Untersuchungen über die Bedeutung der Mikroorganismen für die Entstehung der Diphtherie beim Menschen, bei der Taube und beim Kalbe» (Mitt. a. d. Kais. Gesundheitsamt, B. II, 1884); «Die Aetiologie der Rotzkrankheit» (Arb. a. d. Kais. Gesundheitsamt, B. I, 1886); «Experimentelle Untersuchungen über den Schweine-Rothlauf» (ibid.); «Eine neue Methode zur Färbung der Mikroorganismen, insbes. ihrer Wimperhaare und Geisseln» (ibidem B. VI, 1889); «Über Epidemien unter den im Hygienischen Institut zu Greifswald gehaltenen Mäusen» (Cntrbl. f. Bakteriologie, Abt. 1, B. IX, 1891); «Bericht der Komission zur Erforschung der Maul- und Klauenseuche» (Deutsche med. Wochenschr., 1898, № 5-6).