THE AMERICAN V.v. 



MONTHLY 



MICROSCOPICAL JOURNAL. 



Vol. XV. JANUARY, 1894. No. i. 



On the Study of Yeasts, With Descriptions of the Hansen 



Culture Box and of a New Infection Needle for the 



Study of Lower Organisms. 



By J. CHRISTIAN BAY, 

 Bacteriologist of the Iowa State Board of Health. 



, AMES, IOWA. 



WITH FRONTISPIECE. 



The study of tlie yeasts is one of the most interesting 

 and instructive in botany. The material is easily ob- 

 tained, and the student has ample opportunity to become 

 acquainted with cell physiology. The yeasts are often 

 studied in botanical and other biological laboratories, 

 but a great many workers have not had the opportunity 

 of becoming acquainted with the latest methods in this 

 sj)ecial branch, such as it has developed, during the last 

 decennium, in the central laboratories for the physiology 

 of fermentations, namely in the laboratories of Emil Chr. 

 Hansen and Alf. Joergensen. The following notes will 



EXPLANATION OF PLATE. 



Fig. 1. a, cells of Saccharomyces cerevisiae I Hansen : b, cells of S. pas- 

 torianus I Hansen. 



Fig. 2. Spore-forming cells : a, of S. cerevisiae I Hansen : b, of S. pasto- 

 rianns I Hansen : c, of the same as in a ; formation of spores not yet com- 

 pleted, trace of sport-s : d, trace of spores in the same as in b. 



Fig. .3. The Hansen Culture Box : AA, slide door with : aa, a cross-bar at 

 the top. 



Fig. 4. a, S. cerevisiae I Hansen : b, Mouilia Candida. 



Fig. 5. a, Saccharomyces cerevisiae I Hansen : b, [Saccharomyces] api- 

 culatus Reess : c, Mycoderma cerevisiae : d, S. pastorianus III Hansen. 



