STUDIES ON FERMENTATION. 



27 



Let us take a glass flask having a long neck (Fig. 3 a), and 

 holding from 250 c.c. to 300 c.c. {i.e., about 9 or 10 fl. oz. ) ; 

 let us put into it some wort, hopped or not, and then draw 



out the neck of the flask in the flame of a lamp, so as to 

 give to it the shape b (Fig. 3) ; let us next heat the liquid 

 to the boiling point, when the steam will rush with a 

 hissing sound out of the curved end. We may then, 

 without further precaution, permit our flask to cool, or, as 

 an additional safeguard, we may introduce a small quantity of 

 asbestos into the open extremity, at the very moment when the 

 flame is taken away from the flask. Before introducing the 

 asbestos, we may pass it through the flame, and we may repeat 

 this after it has been placed in the end of the tube.* The air 

 which first re-enters the flask must come in contact with the 



turbid, under a microscope, we shall be amazed at the wonderful number 

 of strange microscopic organisms that swarm on the surface of the grains 

 and on the sides of the cistern. There is no doubt that their presence is 

 injurious to germination, inasmuch as they absorb much oxygen ; more- 

 over, they acidify the grain and cause it to deteriorate. 



* In these experiments the asbestos is only introduced by way of 

 extra precaution. Originally, in his early experiments in connection 

 with the subject of spontaneous generation, the results of which were 

 published in 1860-62, the author did not use it, and he observed no 

 ill effects resulting from the omission ; now, however, he constantly 

 makes use of it. In studies of this kind novel precautions are never 

 thrown away ; moreover, the presence of this asbestos is a sure bar to 

 the entrance of insects. The author has preserved for a long time a 

 flask, in the slender neck of which an insect is contained; he killed it 

 with a flame just as it was approaching the liquid. Quite recently, M. 

 Calmettes, a young engineer from the Ecole Centrale, when engaged, at 



