On the Dcvelopmeyit o/" Bacteria i'/i Organic Infusions. 173 



After four days the infusion in capsules 1, 2, 5, and 6 was found 

 to be teeming with Bacterium termo and Bacterian filaments. 



Capsule 3 was found to be cracked, and hence was discarded 

 (it swarmed with Bacteria). 



Capsule 4 was perfectly free from organisms, and remained so 

 during a fortnight, when a fungus-mycelium made its appearance 

 on the surface. 



Series F. Dec. 10th. — -A strong Infusion of turnip and cheese, 

 prepared as in Series B (sp. gr. 1<J13), was boiled in an eight-ounce 

 flask for five minutes. Three common test-tubes were superheated 

 and placed in a beaker to support them. 



Xo. 1. The infusion was poured in, and with it one drop of 

 distilled water. 



No. 2. The infusion was poured in and thus left. 



No. 3. The infusion was poured in and again boiled for two 

 minutes. 



These and the flask containing the remaining infusion were left 

 on a shelf for one day; on Dec. 11, there being no cloudiness in any 

 of the four, they were placed on the top of the hot-air bath. On 

 Dec. 13 No. 1 was found to be swarming with Leptoihrix-gTOwt\is 

 and free Bacterium termo. 



No. 2 also was cloudy and swarmed with what Cohn calls the 

 rosary-chains. No. 3 was absolutely free from all development of 

 life, and was perfectly sweet and limpid ; so also was the fluid in 

 the original flask, a large one capable of holding eight ounces. 

 How is the development of Bacteria in No, 2 to be explained? 

 The original fluid remains pure ; the fluid in No. 3, which was 

 reboiled, remains so too ; the tube itself. No 2, had been heated 

 red-hot and could not be a source of contamination. One's 

 attention was therefore directed to the conditions of the passage 

 of the fluid from the flask into the tubes ; and here an explana- 

 tion at once offered itself. The large flask luicl not been super- 

 heated; its lip was still dirty, laden with Bacteria ready to con- 

 taminate fluids as they poured from it ; hence the contamination of 

 the fluid in test-tube No. 2. The validity of this explanation can- 

 not be disputed, because it is known that such glass surfaces, 

 unless specially cleansed, invariably contaminate infusions exposed 

 to them. 



Series G. Feb. 11th. — The publication of Dr. Burden Sander- 

 son's letter, describing some experiments made by Dr. Bastian, 

 induced us to make a further series of expeiiments with impor- 

 tant modifications. We had expressly avoided the introduction of 

 any thing like visible lumps of solid cheese or turnip into our 

 infusions during their ebullition, believing that such lumps were 

 a possible source of the exclusion of Bacteria or their germs from 

 the killing influence of the boiling temperature. This precaution 

 we had supposed (in the absence of any statement to the opposite 

 effect) to have been taken by Dr. Bastian in the experiments 

 adduced by him in the ' Beginnings of Life.' The presence of such 

 lumps was publicly suggested in discussion at the British-Asso- 



Ann.d: ^fag. K. H. Ser. 4. Vol xiii. 13 



