1894.] MICROSCOPICAL JOURNAL. 5 



25° C in 40 h. 15° C in 40 h. 15° C in 72 h. 



Cultivated yeast t) 



Wild yeast 



How is the spore-cultiire to be carried out f 

 When the sample for microscopic examination has been 

 taken out, the bottle containing the yeast emulsion 

 should be set apart, and the yeast allowed to settle at 

 the bottom. After this, the fluid is almost completely 

 emptied out, and only a few drops are left with the bot- 

 tom layer of yeast. This may be done comparatively 

 safely in the Hansen Box mentioned below. When the 

 bottle has been flame-sterilized at the outside, it is placed 

 in the box, corked. 



The apparatus for spore-cultivation consists of a pair 

 of small culture dishes* embracing a piece of gypsum, 

 the dimensions of which are about ? of an inch smaller 

 than those of the smallest of the dishes. Such aj^para- 

 tus should always be kept, steam-sterilized and wrapped 

 in filter paper, in store. They are flame-sterilized on 

 the outside, and put into the box with a wash-bottle of 

 sterilized water, also flame-sterilized. In the box, the 

 cover is taken off the dish with the gypsum, the yeast- 

 bottle is shaken up, and one or two drops of the thick 

 yeast-emulsion allowed to fall on the surface of the dry 

 gypsum bloc. The cork is then replaced. After this, 

 the gypsum is charged with sterilized water from the 

 wash bottle. t The cover dish must, in accordance with 

 rule 2 (see above) not fit closely, but air must be allowed 

 to pass over the yeast layer. This is effected by a small 

 piece of rubber, wood, etc., placed between the edges of 

 the two dishes, and kept in the laboratory for that use in 



*See Salomonsen's Bacteriol. Technology (W^ood's Med, and Surg. Monogr. 

 IV, 2, page 463.) 



fPerfect soaking of the gypsum is recommendable, the water is, therefore, 

 added twice, successively. W^hen the bloc is soaked in the middle, this con- 

 tion is fulfilled. 'Chen, some water must stand around the gypsum (not above 

 it), between this and the glass. 



