336 



Prof. H. C. Bastian on the Heat 



to the widespread distribution of aerial germs of Torulce wholly unne- 

 cessary, by showing that certain fluids, by reason of certain intrinsic 

 peculiarities, when they undergo fermentation give rise to Torulce only. 

 We are thus led to conclude that whilst some fluids are capable of en- 

 gendering both kinds of organisms, others tend only to produce one or other 

 of them — whether the fluids are contained in closed flasks or in open 

 vessels exposed to the incidence of atmospheric particles. I have more 

 than once seen nothing but Torulce appear in an infusion of turnip ex- 

 posed to the air after it had been heated in a closed tube to a temperature 

 of 293° F. for twenty minutes, and I have once seen the same thing occur 

 in an unheated infusion of turnip exposed to the air, though on all other 

 occasions such infusions have swarmed only with Bacteria and Vibriones. 

 On the other hand, a boiled ammonic-tartrate solution exposed to the air, 

 though protected from an excess of atmospheric particles (for the advent 

 of a large number of these might in some cases incite putrefaction), is 

 never found to contain Bacteria ; the fluid continues clear, though a 

 sediment gradually accumulates at the bottom of the flask, amongst which 

 Torulce and other fungus-germs are constantly to be found — more nume- 

 rous though otherwise very similar to those which are to be met with in 

 flasks closed during ebullition, or in others to which only filtered air is 

 admitted. Although Torulce only appear in such fluids, they continue all 

 the time to be eminently inoculable by Bacteria ; and, again, when the 

 Torulce begin to decay they are apt to incite a more or less manifest 

 putrefaction, during which the fluid gradually becomes turbid with Bacteria. 

 It is, in fact, a general rule that putrefaction is apt to supervene upon 

 a fermentation of a more smouldering type. 



III. In the third subclass I include fluids which, after exposure to 

 212° F. or higher temperatures, are unable, either alone or under the in- 

 fluence of ordinary atmospheric particles or fragments, to undergo putre- 

 faction, although such a process can invariably be initiated by bringing 

 the fluids into contact with living ferments. As examples of such fluids, 

 I may cite the neutral saline solution to which I have so often referred 

 and that known as Pasteur's solution. Other fluids of the same kind 

 have lately been referred to by Professor Huizinga*. The fact that 

 certain fluids cannot be made to undergo putrefaction by the influence of 

 dead organic particles, although they become at once amenable to the in- 

 fluence of living units, unmistakably shows the superior potency of living 

 ferments ; their action has, moreover, invariably proved to be certain 

 and inevitable in all the cases in which they were known to be present. 

 Even these least fermentable fluids of our third subclass invariably be- 

 come turbid within three days after inoculation with living units, if main- 

 tained at a temperature of about 70° F. ; whilst when other more change- 

 able fluids are inoculated, putrefaction ensues with equal certainty, though 

 with much greater rapidity. 



* See ' Nature,' March 20th, 1873, p. 380. 



