Page:Diphtheria - a lecture delivered at the Norfolk and Norwich Hospital (IA b22345656).pdf/20

 a family which it has once invaded, is to be attributed in some degree to the persistence of the same cause as originated the first case. What that cause is, is as mysterious as the cause of any other epidemic disease. It is futile to attribute it, as is done without due reflection, to poverty, want of cleanliness, over-crowding, cesspools, dung-heaps, and other items in the unsavoury catalogue which has commonly the discredit of every epidemic visitation. Stench and insufficient diet, and filthy and over-crowded rooms have ever been the sad heritage of the agricultural labourer, but diphtheria is of recent origin. Doubtless, these insanitary adjuncts to the labourer's life predispose him and his children to the assault of any epidemic malady, but the specific cause of diphtheria, as of other forms of disease, is a something superadded which our senses cannot appreciate. Whether it be the sporules of a fungus permeating the atmosphere, and absorbed through the lungs into the blood, as suggested by Dr. Laycock, must as yet remain sub judicé. All that we can affirm in the present state of knowledge is, that anti-hygienic condi-