1224 



with water to wliich is added some calciiim-caibonate, then heated 

 for a few seconds to 90° or 100° C. Kept at 30° to 40° C. there 

 iisuall} resnlts after two days a strong butjric-acid feinientution 

 in which occur various butyric-acid bacteria which are then to be 

 isolated. 



For tiie preparation of a crude butyl-alcoholic fermentation crushed 

 corn *) of Hoi'deum vulgare nudum may be used ; a pap of potatoes 

 infected with soil and heated not higher than 80° to 85° C. will 

 also do; addition of chalk is not necessary, the butyl bacteria 

 producing no acid. Of course the spores of butyric-acid ferments are 

 still present in such preparations and the surprising fact that by 

 application of the said tempei-ature no butyric-acid but a butylic 

 fermentation ensues, should |)robably be attributed to the injurious 

 action of the butyl alcohol on the butyric-acid ferments. 



The pure culture is effected as follows. 



Malt-infusion agar with 5° to 10° glucose is liquetied and aftei' 

 cooling to near solidificatio)! and addition of a great quantity of 

 Oidium lactis is plated (Op) in a large glass dish {G^^}. At a temperature 

 of 25° to 28° C. the whole surface of the plate is already after 

 24 hours covered with a thick snow-white film of conidia and the 

 interior of the agar is wholly interwoven with mycelium, which 

 causes a considerable absorption of oxygen. 



A second malt-infusion-agar plate (Kd) without Oidium is now 

 prepared in a glass dish {Gs^), much smaller than Gó\. The space 

 between Gö\ and Gs, must be large enough 6^.9j to be caught with the 

 fingers. On its surface a little of the material containing the anaerobes, 

 that is of the crude butyric-acid or butyl-alcoholic fermentations, 

 diluted with sterile water, is spread. Now the lid of the smaller 

 dish {Gs^) is removed and the plate pressed on the Oidium plate 

 the agar side ijia) upward as shown in the figure. 



For the escaping of the air from Lr a little hole g is bored in 

 the glass wall of 6^.s-, and closed with a droplet of paraffin intro- 

 duced with a heated glassrod. At 28° to 30° C. the air in L?", which 

 space can be relatively small, will soon be free from oxygen and 

 the anaerobes on Ka can begin to grow. To further the absorption 

 of oxygen from the agar Ka in Gs^, Oidium may also be added 

 to it, but then a thin layer of mall agar without Oidium should be 

 poured on the surface of Ka to obtain a germ-free surface for the 

 sowing of the anaerobes. Oidium being strictly aerobic the mycelia 

 do not perceptibly grow through this protecting layer. 



b Fermentation el ferments butyliques. Archives Néerlandaises I. 39. Pag. 1. 

 Bactéries actives dans le voisinage du lin. ibid. Sér. '2. 1. 9. p. 41S. 1904. 



