838 FRAGMENTS OF SCIENCE 



"What present warrant," it has been asked, "is there 

 for supposing that a naked, or almost naked, speck of 

 protoplasm can withstand four, six, or eight hours' boil- 

 ing?" Regarding naked specks of protoplasm I make no 

 assertion. I know nothing about them, save as the creat- 

 ures of fancy. But I do affirm, not as a "supposition," 

 nor an "assumption," nor a "probable guess," nor as "a 

 wild hypothesis," but as a matter of the most undoubted 

 fact, that the spores of the hay bacillus, when thoroughly 

 desiccated by age, have withstood the ordeal mentioned. 

 And I further affirm that these obdurate germs, under the 

 guidance of the knowledge that they are germs, can be de- 

 stroyed by five minutes' boiling, or even less. This needs 

 explanation. The finished bacterium perishes at a tem- 

 perature far below that of boiling water, and it is fair to 

 assume that the nearer the germ is to its final sensitive 

 condition the more readily will it succumb to heat. Seeds 

 soften before and during germination. This premised, the 

 simple description of the following process will suffice to 

 make its meaning understood. 



An infusion infected with the most powerfully resistent 

 germs, but otherwise protected against the floating matters 

 of the air, is gradually raised to its boiling-point. Such 

 germs as have reached the soft and plastic state imme- 

 diately preceding their development into bacteria are thus 

 destroyed. The infusion is then put aside in a warm room 

 for ten or twelve hours. If for twenty -four, we might have 

 the liquid charged with well-developed bacteria. To an- 

 ticipate this, at the end of ten or twelve hours we raise 

 the infusion a second time to the boiling temperature, 

 which, as before, destroys all germs then approaching 

 their point of final development. The infusion is again 



