RESULTS OF SCIENTIFIC RESEARCH IN PRACTICE. 213 



The wort is introduced into the lower cylinder, where it 

 is treated in the ordinary manner. The pure culture is 

 introduced into the upper cylinder, and is then washed down 

 into the lower cylinder by means of a little wort, which is 

 forced from B into A, and then back again into B. When a 

 vigorous multiplication of the yeast has set in, the liquid is 

 stirred up and a portion forced into A ; this is to be used to 

 start the next fermentation. The cylinder B thus serves 

 alternately as fermenting-cylinder and wort-cylinder. 1 



Other modifications have been devised by Brown and 

 Morris, Elion, Kokosinski, and Van Laer', more widely 

 different are the forms devised by P. Lindner and Marx. 2 



In order to be able to send to a distance the selected 

 pure cultures in a liquid condition, a special form of flask 

 was devised by Hansen. The yeast can be sent to great 

 distances in these flasks, and there is no difficulty in safely 

 transferring it from the flask to the cylinder of the propa- 

 gating apparatus. 



In sending small quantities of pure cultures, and in 

 such a manner that they may be safely and readily employed 

 for further cultivation, the small Hansen flasks (page 20) 

 are employed. They are connected, in the flame, with the 

 Pasteur flask in which the pure culture has developed. A 



1 Both the above described forms of apparatus are manufactured by 

 Messrs. Burmeister and Wain, of Copenhagen; Hansen and Kuhle's 

 apparatus is also made by W. E. Jensen, of Copenhagen. 



2 An apparatus which has now become of considerable importance as 

 a link in Hanserfs system of pure yeast cultivation is the closed cooler 

 mentioned above, by means of which it is possible to introduce the wort 

 into the fermenting-vessel absolutely pure and properly aerated. Ap- 

 pliances having this for their object were devised by Velten shortly after 

 the publication of Pasteur's " Etudes," and were constructed in accordance 

 with Pasteur's theoretical views, but hitherto they could not acquire any 

 practical importance ; for what was the use of having a pure wort when 

 the disease-germs were again introduced with the yeast ? The conditions 

 which render such appliances useful are only now attaine d through the 

 introduction of pure yeast, and the open coolers will therefore gradually 

 disappear in the future. 



