182 On the Phenomena of Putrefaction and Infection. [Jan. 13, 



preservative of a class : — On the 30th of November a quantity of animal 

 refuse, embracing beef, fish, rabbit, hare, was placed in two large test- 

 tubes opening into a protecting-chamber 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 boiled and abandoned to the action of the foul 

 " sewer-gas " emitted by their two putrid companions. On Christmas- 

 day 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 the infected turnip was transferred to the whiting ; on the 28th 

 disease had taken entire possession of the whiting. To the present hour 

 the beef- and mutton-tubes remain as limpid as distilled water. Just as 

 in the case of the living men and women in Edinburgh, no amount of 

 fetid gas had the power of propagating the plague as long as the 

 organisms which constitute the true contagium did not gain access to 

 the infusions. 



The universal prevalence of the germinal matter of Bacteria in water 

 has been demonstrated with the utmost evidence by the experiments of 

 Dr. Burdon Sanderson. But the germs in water are in a very different 

 condition, as regards readiness for development, from those in air. In 

 water they are thoroughly wetted, and ready, under the proper condi- 

 tions, to pass rapidly into the finished organism. In air they are more 

 or less desiccated, and require a period of preparation more or less long 

 to bring them up to the starting-point of the water-germs. The rapidity 

 of development in an infusion infected by either a speck of liquid con- 

 taining Bacteria or a drop of water is extraordinary. On the 4th of 

 January a thread of glass almost as fine as a hair was dipped into a 

 cloudy turnip-infusion, and the tip only of the glass fibre was introduced 

 into a large test-tube containing an infusion of red mullet. Twelve 

 hours subsequently the perfectly pellucid liquid was cloudy throughout. 

 A second test-tube containing the same infusion was infected with a 

 single drop of the distilled water furnished by Messrs. Hopkin and 

 "Williams ; twelve hours also sufficed to cloud the infusion thus treated. 

 Precisely the same experiments were made with herring with the same 

 result. At this season of the year several days' exposure to the air are 

 needed to produce the same effect. On the 31st of December a strong 

 turnip-infusion was prepared by digesting in distilled water at a tem- 

 perature of 120° Eahr. The infusion was divided between four large 

 test-tubes, in one of which it was left unboiled, in another boiled for five 

 minutes, and in the two remaining ones boiled and after cooliug infected 

 with one drop of beef-infusion containing Bacteria. In twenty-four 

 hours the unboiled tube and the two infected ones were cloudy, the 



