THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL 



Voi,. XV. FEBRUARY, 1894. No. 2. 



On the Study of Yeasts, With Descriptions of the Hansen 



Culture Box and of a New Infection Needle for the 



Study of Lower Cryptogames. 



By J. CHRISTIAN BAY, 



Bacteriologist of the Iowa State Board of Health. 



DES MOINES, IOWA. 



{Continued from page 11.) 



In the first part of this paper we have outlined the 

 means of obtaining endospores in yeast. The budding 

 is the main form of propagation ; only in three species 

 of those known at present, spores occur in the ferment- 

 ing fluid, viz. : S. meinbranaefaciens, S. ludroigii and 8. 

 anonialus. We came so far that we were able to dis- 

 tinguish between a cultivated and a wild form ; this is 

 all that is required for the common yeast analysis in 

 breweries. The number of " wild " cells may be ascer- 

 tained by examining the spore culture by means of a 

 hsematimeter ;* it is impossible to obtain useful results 



EXPLANATION OF PLATE. 



Fig. 1. Microscopic picture of yeast 

 sample submitted to pure cul- 

 tivation. 



Fig. 2. Boettcher's (model of a) moist 

 chamber, adapted to the Han- 

 sen method of absolute pure 



section; a, cover; b, gelatine 

 layer; c, g'ass ring; d, slide; 

 e, drop of water. 



Fig. 8. The same seen from above be- 

 fore inoculation. 



Fig. 9. The same after iucnlation; 



cultivation (see text). ; 27 mature colonies seen through 



Fig. 3. S. cerevisiaj I (var. easily ! the slide. The two colonies in 



forming spores). plots G and 10 are too clo.se to- 



Fig. 4. S. Pastorianus III. ' gether, and should not be used 



Fig. 5. S. cerevisiai I (var. not easily in the preparation of the flask 



ferming spores). cultures. The outlines of the 



Fig. 6. a. Spores of 3. gelatine laj'er are indicated (d). 



b, same of 2. | a, slide of the chamber; c, glass 



Fig. 7. The -moist chamber, vertical j ring in Figs. 8 and 9. 



*See Jenaische Gesellsch. f. Medicin und Naturwiss, 1878, p. 1-18. 



