130 



Royal Society : — 



an infusion of hay, the third with solution of gelatine, and the 

 fourth with water that had been in contact with putrid meat. The 

 hay and putrid-meat solutions were taken because they had often been 

 used by other investigators ; sugar was employed, being a well- 

 defined organic compound free from nitrogen which can easily be 

 obtained in a state of purity ; and gelatine was used as a nitrogenized 

 body which can be obtained pure and is not coagulated by heat. 



To carry out the experiments I prepared a series of small tubes 

 made of very thick and well-annealed glass, each tube about four 

 centimetres in length, and having a bore of five millimetres. The 

 fluid to be operated upon was introduced into them, and left exposed 

 to the atmosphere for sufficient length of time for germ-life to be 

 largely developed. Each tube was then hermetically sealed and 

 wrapped in wire gauze, to prevent any accident to the operator in 

 case of the bursting of any of the tubes. They were then placed in 

 an oil-bath, and gradually heated to the required temperature, at 

 which they were maintained for half an hour. 



Sugar Solution. — A solution of sugar was prepared by dissolving 

 1 part of sugar in 10 parts of water. This solution was made with 

 common water, and exposed all night to the atmosphere, so that life 

 might impregnate it. The fluid was prepared on the 1st of Novem- 

 ber, 18/0, introduced into tubes on the 2nd, and allowed to remain 

 five days. On the 7th of November twelve tubes were kept without 

 being heated, twelve were heated to 212° Fahr., twelve to 300°, and 

 twelve to 400° Fahr. 



The contents of the tubes were microscopically examined on the 

 1st of December, twenty-four days after heating. 



Sugar solution 

 not heated. 



There were about 

 30 animalcules 

 under each field 

 of the micro- 

 scope, principal- 

 ly small black 

 vibrios, 2 or 

 3 microzjmes 

 swimming slow- 

 ly ahout, 3 or 4 

 ordinary/ swim- 

 miftg vibrios, and 

 a few Bacteria. 



Heated for half 

 an hour at 

 212° Fahr. 



A great portion 

 of the life had 

 disappeared, no 

 animalcules were 

 swimming ; still 

 this temperature 

 had not com- 

 pletely destroy- 

 ed life. 4 or 5 

 small black vi- 

 brios were oh- 

 served moving 

 energetically to 

 and fro ; 2 or 3 

 ordinary vibrios 

 were also ob- 

 served moving 

 energetically in 

 the same posi- 

 tion of the field ; 

 that is, without 

 swimming about. 



Heated for half 

 an hoiu* at 

 300° Fahr. 



The sugar was 

 slightly charred, 

 but the life was 

 not entirely de- 

 stroyed, as 1 or 

 2 ordinary vi- 

 brios and 1 or 2 

 small black vi- 

 brios were ob- 

 served in motion 

 under the field 

 of the micro- 

 scope. 



Heated for half 

 an hour at 

 400° Fahr. 



The sugar was 

 almost entirely 

 decomposed; no 

 trace of life was 

 observed. 



Heated for half 

 an hour at 

 500° Fahr. 



No life observed. 



