1891.] Dr. Edward E. Klein on Infectious Diseases, 277 



WEEKLY EVENING MEETING, 



Friday, February 20, 1891. 



Sir James Criohton Browne, M.D. LL.D. F.E.S. Treasurer and 

 Vice-President, in the Chair. 



Edward E. Klein,. M.D. F.E.S. Lecturer on Physiology 

 at St. Bartholomew's Hospital. 



Infectious Diseases, their Nature, Cause, and Mode of Spread. 



Wb read in Homer that " Phoebus Apollo, offended by mortals, sent 

 a pernicious plague into the camp of the Greeks ; the wrathful god 

 with his arrows hit first mules, then dogs, and then also the Greeks 

 themselves, and the funeral pyres burned without end." If we ex- 

 pressed this in less poetical language, but more in conformity with 

 our modern realistic notions, we would say that the deity of health 

 and cleanliness, having been offended by mortals, sent his poisonous 

 but imperceptible darts or bacilli into them, and caused an epidemic 

 of a fatal disease, communicable to man and animals. 



In whatever form we meet with this simile — vthether an epidemic 

 be ascribed to a wrathful Providence, or to a sorcerer or a witch that 

 put their spells on man or on cattle, thereby causing numbers of them 

 to sicken and to die ; whether this happened amongst the nations of 

 old, or amongst the modern Zulus, whether amongst the peasants 

 of Spain or in Italy — we now know that it always means that the 

 offended deity of cleanliness, and the outraged laws of health, avenge 

 themselves on mortals by the invasion of armies of imperceptible 

 enemies, which we do not call arrows, nor sorcerers' or witches' 

 spells or incantations, but microbes. 



From Homer's Trojan epidemic among the Greeks to the epidemic 

 in the camp of Cambyses, from the plagues carried and spread by the 

 Crusaders of old to the plagues carried and spread in modern times 

 by pilgrims to and from Mecca, the plagues following the ancient 

 armies and those of more recent times, the plagues attacking a country 

 debilitated by famine or by superstition have been in the past, and 

 will be in the future, due in a great measure to neglect and ignorance, 

 on the part either of individuals or of a whole population, of the 

 principles of the laws of health : and it is chiefly to this neglect, 

 ignorance, and indolence, that the spread and visitations of epidemic 

 infectious disorders must be ascribed. It is therefore, with justice, 

 that these disorders are called preventable diseases, and one cannot 

 imagine a greater contrast than that between the knowledge we possess 

 at the present time of communicable diseases, as to their cause, mode 

 of spread and prevention, and the views of lormer generations as to 

 tlieir spontaneous origin. 



