necessary to kill Bacteria, Vibriones, fyc. 335 



Many of the fluids which habitually remain clear after a previous ebul- 

 lition in flasks whose necks have been plugged with cotton-wool, many 

 times bent, or hermetically sealed after the entry of calcined air, or when 

 enclosed in vessels which are completely full (in Grruithuisen's fashion), 

 belong to this subclass. In other cases, however (as in many of those 

 instances where urine or hay- or turnip-infusions have been employed), 

 those who do not content themselves with a mere naked-eye inspection of 

 the apparently pure fluids would find on microscopical examination of 

 the sediment that such fluids were to a low degree self-fermentable — 

 that they correspond, in fact, with group E of the last subclass*; whilst, 

 in addition, my researches have shown that many of such fluids are 

 capable of being rendered self -fermentable to a marked degree, if, instead 

 of subjecting them to contact with calcined air or variously filtered air, 

 its reflux after ebullition is altogether prevented by hermetically sealing 

 the neck of the flask during ebullition. Operating in this way, I have 

 repeatedly found that fluids freed from the pressure of air and from its 

 influence altogether become to a marked extent self -fermentable, although 

 the same fluids exposed to filtered or calcined air under ordinary atmo- 

 spheric pressure remain unaltered and barren, or at most exhibit the 

 very low degree of f ermentability referred to as characterizing group E f. 

 But just as amongst the self-fermentable fluids we find there are some 

 which only engender Torulce or other allied fungus-germs, so now we find 

 that some previously boiled fluids, even when fully exposed to the air, 

 swarm only with Torulce. Those exciting agents derived from the atmo- 

 sphere which, with one set of fluids, initiate changes leading to the evolu- 

 tion of Bacteria, with another set lead only to the evolution of Torulce. 

 And whilst telling us that the Bacteria which appear in previously barren 

 fluids after exposure to air are not due to their contamination with germs 

 of Bacteria, some observers would have us conclude that the Torulce 

 which appear in other previously barren fluids after a similar exposure 

 are the products of preexisting aerial germs of such organisms. This 

 conclusion, however, cannot readily be accepted in the face of the evidence 

 derived from the closed-flask experiments with self-fermentable fluids of 

 the lowest degree %. Such experiments, in fact, render the hypothesis as 



also a record of other experinients'inade with the air of alpine regions by MM. Pouchet, 

 Joly, and Musset, in Compt. Bend. Sept. 21, 1863. 



* Other fluids richer in organic matter or otherwise more favourably endowed, in- 

 stead of presenting this low degree of self-f ermentability, are notably prone to undergo 

 change wben we attempt to preserve them in the manner described, although such 

 modes of preparation do suffice for preserving so many fluids. This has been fully 

 admitted by Schrceder and Dusch, Schwann, Pasteur, and others. 



f In illustration of this statement see ' The Beginnings of Life,' Appendix C, Exps. 

 viii., ix., xiv., xv., xviii., xx., xxvi.,xxx., xxxiiL, and xxxvi. 



\ The only evidence in favour of such a conclusion is not one jot more conclusive 

 than that which was formerly adduced in favour of the universal prevalence of Bacteria- 

 germs in the air. 



