60 PURE CULTURES OF 



The different forms of apparatus mentioned above are 

 only very imperfectly known to me, and I have never tested 

 them. On the other hand, I have had an opportunity of 

 testing the apparatus shown in Figs. 13 and 14. It is 

 manufactured by a Danish firm of repute (Burmeister and 

 Wain, of Copenhagen), and I therefore recommend it to 

 those who prefer this form. In the most essential points 

 the two forms of apparatus are identical. The new apparatus 

 was devised by Messrs. Bergh and Jorgensen who have 

 obtained patent rights both at home and abroad. Fig. 13 

 shows the whole apparatus complete with its adjuncts. X 

 is a filter through which the air passes on its way to the 

 pump ; V is the air-pump with its pipe < leading to the air- 

 holder U, and from this the pipe Z Y leads to the filter D, 

 and thence to the propagating apparatus. The filtered 

 sterile air passes into this through the three side tubes 

 A, B and C, provided with three-way cocks. (These cocks 

 require very careful and accurate manipulation, as otherwise 

 serious mistakes may easily be made.) The two cylinders 

 A and B are made of copper, but with brass bottoms. A 

 has a capacity of about 48 liters, and B a capacity of 160 

 liters. The former is provided with a stirrer E, and a tube a 

 for introducing the yeast and for withdrawing small samples, 

 this last being effected by the aid of compressed air. The 

 bent tube F provides an exit for the carbonic acid gas ; G P 

 is a wider tube uniting the two cylinders A and B, and this 

 connecting pipe may be opened or closed by the cock G. 

 H is an outlet for the water used in cleaning the apparatus. 

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

 two parts ; through the top passes a closed tube for intro- 

 ducing a thermometer into the cylinder. The upper portion 

 of the jacket is for the cold water used in cooling the wort, 

 and it can also be used for regulating the temperature during 

 fermentation. The lower portion forms a steam-jacket, and 



