M. MATERIA MEDICA, THERAPEUTICS, AND HYGIENE. 545 



cavity produce most intense pathological effects, but finally 

 disappear entirely, and without leaving a trace, whenever the 

 organism does not succumb. Inaugural Disc, of Dr. Black, 

 Stettin, 1810. 



TEMPERATURE REQUIRED TO KILL MICROSCOPIC ORGANISMS. 



The discussion of experiments made in regard to spontane- 

 ous generation has proceeded upon the assumed basis that 

 live germs are destroyed by exposure to a heat of 212, or 

 that of boiling water. Suspecting that this might not be true 

 in all cases, Mr. Crace Calvert has lately instituted a series 

 of investigations on the subject. Different substances w T ere 

 employed by him, particularly such as have generally formed 

 the basis of experiments namely, solutions of sugar, infusion 

 of hay, solutions of gelatine, and water that has been in con- 

 tact with putrid meat. Small tubes were selected of very 

 thick and well-annealed glass, each tube about four centi- 

 metres long and five millimetres in diameter of bore. The 

 substances to be operated upon were introduced into them, 

 and left exposed to the atmosphere long enough for the germ 

 life to be developed. Each tube was afterward hermetically 

 sealed, and wrapped in wire-gauze to prevent any accident to 

 the operator in case of the bursting of the tube. They were 

 then placed in oil baths, and gradually heated to the required 

 temperature for half an hour. "Without going into the de- 

 tails of experiment, we may mention, as the general result, 

 that protoplasmic life was found to be only slightly affected 

 by a temperature of 212, and that even at 300 it is not en- 

 tirely destroyed, except in the case of gelatine. In another 

 case the temperature of 400 Fahr. was required to destroy 

 life. 



These experiments, therefore, show that the life found by 

 previous experimenters in boiled liquid was not due to spon- 

 taneous generation, but to life which had remained in the 

 fluids, as in none of the experiments on record, as made by 

 the advocates of the spontaneous generation theory, was heat 

 raised above a temperature of 300. 



Proceeding to the other extreme of temperature, Mr. Cal- 

 vert subjected some putrid meat liquor, containing a large 

 quantity of animalcules, for twenty hours to a temperature 

 ranging between that of the freezing point of water to 11 



