The Evolutio7i of Medical Science. 149 



sewerage connects miles of houses together, and the germs 

 of intestinal diseases in abundance find their way from 

 house to house, unless the plumbers have done their work 

 faithfully and well. I say the germs of disease do this. 

 Scientifically, I mean the spores or seeds of such germs as 

 develop in this manner. The term germs, of course, is 

 here used as synonymous with micro-organisms. Sanitary 

 science insists upon an arrangment of closet, bath and 

 wash-basin pipes that will allow no back pressure of gas 

 from the sewer to force its way into the house and carry 

 such spores.* Sewer-gas is not always deadly or seriously 

 dangerous. This is proven by the fact that men work in 

 it from week to week without impairment of health. f It 

 is always injurious to some constitutions, and is sometimes 

 so to a large number of people. The less of it, therefore, 

 that enters a house, whether disease-laden or not, the better 

 for the average health of the community. 



Scarlet-fever germs come from milk, are carried in 

 clothes, toys, money, books, newspapers, etc. Dogs, cats, 

 and birds, are now charged with transmitting them. 

 Measles, smallpox, whooping-cough, and kindred diseases, 

 journey from patient to patient in similar ways. Bed-bugs 

 are probably very active carriers of contagious diseases. 

 Many investigators are strongly inclined to blame mos- 

 quitoes for transmitting intermittent and remittent fevers. 

 You all know the sticky and transmissable character of 

 lamp-black formed by a smoky lamp. You get it on your 

 fingers first, and soon somebody observes a speck on your 

 face. It is next borne to your clothing, and, whenever two 

 surfaces touch, if one has it, the other gets a little. Dis- 

 ease-microbes are like this, an impalpable powder that 

 every breath of air can blow and every contact of svirfaces 

 divide. Hand gives them up to hand, coat to coat, lips to 

 lips, and even the points of the finest needles are fre- 

 quently laden with and transmit them to the cloth sewn. 

 So small are they that thousands in a single pile cannot be 

 seen by the naked eye. As one grain of wheat will, in a 

 season, produce fifty grains, so one germ, multiplying rap- 

 idly every minute, will form legions in an hour. Of course. 



* Michigan Board of Health Report, 1882, pp. a^i to .3.30. Ibid, pp. 213 to 217. 



tin the discussion following the lecture, Mr. Charles F. Wingate, the Sani- 

 tary Engineer, questioned this assertion of the lecturer, and aflfirmed that ex- 

 perience jiroved all kinds of sewer-gas to be poisonous. Different constitutions, 

 however, differed in their ability to resist these poisonous influences. 



