169;}. J MlCiiOSCOl'lCAi. JOllLNAi.. 17 



Exporiiiu'iits with Wast— A Biolttii^ical Shuly. 



Bv J. \V. SMITH, 



ST. PAUL, MINN. 



A small hit of veast frf)ni a cake of compressed vcast, sus- 

 pended in a drop of water on the <;lass slide of the microscope 

 and examined under the lo\v-j)o\ver <i[lass, was found to he uni- 

 form in composition. The hi<jh power revealed the form of the 

 minute jjlohules of which it was composed. These glohules are 

 unicellular, consisting of protoplasm contained in a cell wall. 

 No nucleus was visii)le, hut a vacuole was plainlv seen. (Fig. i.) 

 This was the appearance of the mass. 



For the studv of the nutrition of veast, Pasteur's fluid was the 

 hasis of the experiments, ^'east in the solution 2 \ liours at the 



^/f r.^.s? 



<a> 



6b @ O 



® ^^ ^ J) 9 ^©^^ ^. ^ 





H'l- 



© 



^- 1^- ^ 13. J=l^. /f. 



temperature of the laboratory, was found to have grown liy hud- 

 ding into such forms as those shown in Fig. 2. 



Experiment i — a. In water 5 hours, at the same temperature, 

 none were found to have more than one bud, and manv none. 



(Fig- 3-) 



Exp. I — I). In So parts water and 15 parts sugar, under the 



same conditions, most of the cells were budded with a single bud. 



(Fig. 4-) 



Exp. I — c. In all the ingredients of Pasteur's fluid but sugar 



a few of the cells were budded, but not so many as in the former 



experiment. 



Exp. I — d. In Pasteur's fluid 6 hours, 20° C, the parent cell 



was budded at each ei^d. and in manv cases the bud was budded. 



(l^ig. 5) ... 



The second series of experiments was also to test the food value 



of various mixtures, but for a longer period of time, 27 hours in 



light at 18° C. 



