RESULTS OF SCIENTIFIC RESEARCH IN PRACTICE. 211 



stirring up the settled yeast, and a cock (I) for drawing off 

 the beer and the yeast. At about the middle of the cylinder 

 there is a small side-tube (j) fitted with india-rubber con- 

 nection, pinch-cock, and glass-stopper. When a portion of 

 the wort has been forced into the fermen ting-vessel, the pure 

 yeast which is forwarded to the brewery in a flask specially 

 constructed for this purpose is introduced through the rubber 

 tube at^'; this is again closed, and the remainder of the wort 

 may then be added either at once or after the lapse of a few 

 days, according to the quantity of yeast which has been 

 introduced. 



Where it is necessary to regulate the temperature during 

 fermentation, the fermenting-vessel is surrounded by a copper 

 water-jacket. 



By means of this simple apparatus it is possible to obtain, 

 at short intervals, absolutely pure pitching-yeast sufficient for 

 about eight hectoliters of wort. As already stated, the 

 apparatus, when once started, works continuously. For 

 further details I refer the reader to the exact description in 

 Hansen's work mentioned above. 



A modification of the propagating apparatus has been 

 devised by Bergh and Jorgensen (Fig. 56). The filtered air 

 passes through the three-way cocks at A, B, and (7, into the 

 two cylinders A and B. The upper cylinder holds about 50 

 liters, and the lower cylinder 160 liters. A is provided with 

 a stirrer (E), a tube (a) for introducing the yeast and with- 

 drawing samples. The bent tube F is for the exit of the 

 carbonic acid. The tube G P connects the two cylinders, and 

 the connection can be made or unmade by means of the cock 

 G. H is the outlet for the water used in cleaning A. 



The cylinder B is surrounded by a cast-iron jacket made 

 in two parts ; the upper portion serves as a water-jacket for 

 cooling the wort and for regulating the fermentation ; the 

 lower portion is used as a steam-jacket, and is provided with 

 a cock at for the entrance of the steam, and another at 8 

 for the outlet. M is a ring-shaped tube provided with small 



