1877.] Putrefactive and Infective Organisms. 237 



be completely removed from the infusions, there is every reason to believe 

 that sterilization iviihout boiling would in most, if not in all, cases be the 

 result. But, passing from probabilities to certainties, it is a proved fact 

 that in numerous cases unboiled infusions deprived of air by five or six 

 hours' action of the Sprengel pump are reduced to permanent barrenness. 

 In a great number of cases, moreover, where the unboiled infusion would 

 have become cloudy, exposure to the boiling temperature for a single 

 minute sufficed completely to destroy the life already on the point of 

 being extinguished through defect of air. With a single exception, I am 

 not sure that any infusion escaped sterilization by five minutes' boiling 

 after it had been deprived of air by the Sprengel pump. These five minutes 

 accomplished what five hours sometimes failed to accomplish in the pre- 

 sence of air. 



The exception here referred to is old-hay infusion, which, though 

 sterilized in less than half the time needed to kill its germs where air is 

 present, maintained a power of developing a feeble but distinct life after 

 having been boiled for a large multiple of the time found sufficient to 

 render infusions of mutton, beef, pork, cucumber, turnip, beetroot, shad- 

 dock, and artichoke permanently barren. 



These experiments gave me the clue to many others which might 

 have readily become subjects of permanent misinterpretation. In the 

 midst of a most virulently infective atmosphere, where, even after some 

 hours' boiling, there was no escape for infusions supplied with air, the 

 expulsion of the air by less than five minutes' boiling in properly shaped 

 retort-flasks, and the proper sealing of the flasks during ebullition, 

 ensured the sterility of the infusions. 



The meaning of a former remark regarding the part played by boiling 

 in establishments devoted to the preserving of meats and vegetables will 

 be now understood. 



The inertness of the germs in liquids deprived of air is not due to a 

 mere suspension of their powers, The germs are Trilled by being deprived 

 of oxygen. For when the air which has been removed by the Sprengel 

 pump is, after some time, carefully restored to the infusion, unaccom- 

 panied by germs from without, there is no revival of life. By removing 

 the air we stifle the life which the returning air is incompetent to 

 restore. 



These experiments on the mortality arising from a defect of oxygen 

 are in a certain sense complementary to the beautiful results of M. Paul 

 Bert. Applying his method to my infusions, I find them sterilized in 

 oxygen possessing a pressure of ten atmospheres or more. Like higher 

 organisms, our Bacterial germs are poisoned by the excess and asphyxied 

 by the defect of oxygen. A mechanical action may also come into 

 play. 



A few short sections on Bacteria germs as distinguished from Bacteria 



