PUTREFACTION AND INFECTION. 119 



the following reiaarkable statement : — ' In one part of it 

 [Edinburgh], congregated together and inhabited by the 

 lowest of the population, there are, according to the 

 Corporation return for 1874, no less than 14,31 9 houses 

 or dwellings — many under one roof, on the " flat " 

 system — in which there are no house connexions what- 

 ever with the street-sewers, and, consequently, no water- 

 closets. To this day, therefore, all the excrementitious 

 and other refuse of the inhabitants is collected in pails 

 or pans, and remains in their midst, generally in a par- 

 ti tioned-off corner of the living-room, until the next 

 day, when it is taken down to the streets and emptied 

 into the Corporation carts. Drunken and vicious though 

 the population be, herded together like sheep, and with 

 the filth collected and kept for 24 hours in their very 

 midst, it is a remarkable fact that typhoid fever and 

 diphtheria are simply unknown in these wretched 

 hovels.' 



The analogy of this result with the behaviour of our 

 infusions is perfect. On the 30th of last November, for 

 example, a quantity of animal refuse, embracing beef, 

 fish, rabbit, hare, was placed in two large test-tubes 

 opening into a protecting-ch amber containing six tubes. 

 On December 13, when the refuse was in a state of 

 noisome putrefaction, infusions of whiting, turnip, beef, 

 and mutton were placed in the other four tubes. They 

 were then boiled and abandoned to the action of the foul 

 * sewer-gas ' emitted by their two putrid companions. 

 On Christmas-day, 1875, these four infusions were limpid. 

 The end of the pipette was then dipped into one of the 

 putrid tubes, and a quantity of matter, comparable in 

 smallness to the pock-lymph held on the point of a 

 lancet, was transferred to the turnip. Its clearness was 

 not sensibly affected at the time ; but on the 26th it 

 was turbid throughout. On the 27th a speck from tlie 

 infected turnip was transferred to the whiting ; on the 



