5 6 ORIGIN OF LO WES T OR GA NISMS. 



several times with the same results. On three occa- 

 sions, I have found the fluid speedily become turbid, 

 which had only been exposed to 131 F. for ten 

 minutes, whilst on three other occasions I have found 

 the inoculated fluid remain clear, after it had been 

 exposed to a heat of 140 F. for ten minutes.* 



* There is, however, another point of extreme interest in con- 

 nection with these experiments, bearing upon the supposed uni- 

 versal distribution of " germs " of Bacteria and other organisms, 

 which I will now mention. One of the flasks, which had been 

 exposed to 140 F., and which had been hermetically sealed at this 

 temperature, had its neck cracked (accidentally) about half an 

 hour afterwards. Thinking it would be as well, notwithstanding 

 this, to keep it and observe the result, its bulb was immersed in 

 the same water-bath with the other flasks which had been pre- 

 pared at the same time. Whilst the fluid in one of these which 

 had been exposed to a heat of 1 3 1 F., became turbid in the course 

 of a few days, this, which had been exposed to a heat of 140 F. 

 and whose neck was also extensively cracked, remained quite clear 

 for seven days, although to such an extent exposed to the access 

 of germs. Its eminent suitability for nourishing the germs of 

 such organisms was also shown, because, on the seventh day, 

 the fluid being still clear, the blade of a penknife was dipped into 

 it, after having been previously immersed in a solution containing 

 living Bacteria and Torulce, and in thirty-six hours after this 

 inoculation, the fluid had become turbid, owing to the presence of 

 myriads of these organisms. So that even where obvious cracks 

 occur, and the vacuum is altogether impaired by the consequent 

 inrush of air, such air does not necessarily carry with it germs of 

 Bacteria which have been supposed to be universally diffused, 

 and capable of passing through cracks so minute as to be in- 

 visible. These results, important as they are, have not at all 

 surprised me, because one may frequently find a previously boiled 

 solution of the kind under consideration, remaining free from 

 turbidity for two weeks or more, although the neck of the flask 

 has been merely covered by a loose paper-cap (see p. 30). 



