STUDIES ON FERMENTATION. 341 



been cooled in contact with the air, and so got charged with 

 disease- germs, will, nevertheless, recover its faculty of keeping 

 for any length of time in pure air, if we again raise its tempera- 

 ture to 80° C. (176° F.) or even 70° or 75° C. {158°, 167° F.) 

 Having filled the tub with the hot wort and put on the lid, wo 

 then connect, by means of a caoutchouc tube c d, the metal tube 

 a c (which opens into one of the tubulures projecting above the 

 lid) with the system of tubes cl e, f g, of which d e is fixed to the 

 cylinder ; e/is a caoutchouc junction connecting e with the bent 

 glass tube g. We then dash over the apparatus, lid, tubulures, 

 and their corks a quantity of boiling water. This collects in the 

 gutter in which the lid rests, and any excess overflows into a 

 second gutter outside the first, where, however, it cannot 

 remain, but passes away by means of a ring of small holes 

 between the base of the outer trough i i and the cjdiuder. The 

 overflow is collected in a third trough at the bottom, whence it 

 can be removed by a pipe M. T is a bent thermometer to indi- 

 cate the temperature of the wort ; its bulb is protected by an 

 mlet socket d d, pierced with holes ; r is a stopcock for dis- 

 charging the water in the gutter, which serves as a hydraulic 

 junction between the cylinder and its lid; R, Y, are stopcocks, 

 or openings for the discharge of the liquid in the cylinder and 

 its deposit. The next process is to cool the vessel, which may 

 be done either by leaving it to itself, or by introducing a cur- 

 rent of cold water through the tubulure E, soldered on to the 

 lid. This tubulure is of the form of an inverted funnel, and is 

 pierced at the bottom with a close row of holes, through which 

 the cold water issues in a sheet over the surface of the cover. 

 In whichever way the cooling is efiected, the external air con- 

 tinues all the time to enter the vessel beneath the lid by way of 

 the long, narrow passage ^/e r/c a, and must necessarily get 

 purified by depositing in its course all fungoid-germs, just as 

 happened in the case of the two-necked flask of air experiments. 

 This, however, may be still further secured by introducing a 

 small plug of cotton wool, or asbestos, into the end of the tube g. 

 The experiments which we have carried out with this appa- 



