PLATE I. 



THE YEAST PLANT. 



Fio. 1. Showing 



/ Cell-wall or sac. 

 A CELT, J Protoplasm (Gr. protos, first; plasma, from plasso, to mould). 



( Vacuolo filled with cell-sap (L. vacuum, an empty space). 

 FIGS. 2, 3, ami 4. Showing 



MULTIPLICATION BY BUDDING OB GEMMATION (L. gemma, a bud). 



The commencement of the process is seen in fig. 2. A bit of protoplasm is pushed out, 

 stretching the cell-wall and making it thin. Fig. 4 shows a cell aggregate or colony produced 

 by a repetition of the process of budding. 

 Fio. 5. Showing 



MULTIPLICATION BY ENDOGENOUS DIVISION (Gr. emlon, within; gennao, I produce). 



The protoplasm collects usually into four round masses, each of which takes on a cell-wall. 

 Culls produced in that way are called Ascospores (Gr. asJcos, a bag; sporu, a seed) or Endo- 

 conidia (Gr. endon, within; Iconis, dust). 

 Fia. 6. Showing 



AS COSFORES set free by rupture of the cell-wall of parent, and multiplying by gemination. 

 Fio. 7. Effect of 



Magenta Stains protoplasm, leaving cell-wall comparatively unstained. 



Crushing Euptures the cell-wall, and shows that the cell-wall is tough and resisting, while the 



protoplasm is semi-fluid. 



Potash (KHO) Dissolves out the protoplasm. 

 Iodine Stains protoplasm. 

 Fio. 8. Measurement by eyepiece micrometer. 



DIAGRAM I. PHYSIOLOGY 



a. Shows the composition of a fluid fit to nourish yeast (Pasteur s fluid). 

 Elements which make cell-wall (C.O.H.). 

 Elements which make protoplasm (C.O.H.N.). 

 Elements which make ash (P.S.K.Mg.Ca.). 



I. Shows the composition of the fluid when acted upon by yeast. Process of fermentation 

 (ferveo, I boil). 



/ Carbonic acid (C0 2 ). 

 Sugar becomes -&amp;gt; Alcohol. 



( Small quantities of succinic acid and glycerine. 

 About two per cent, of sugar is unaccounted for. 

 Ammonium tartrate, etc., used up by the yeast. 



,,, , , f Manufacture of alcohol and carbonic acid, 



lotal result . { 



[ Manufacture of cell-wall and protoplasm. 



CLASSIFICATION OF YEAST. 



Kingdom Plantae, because it possesses a cell-wall made of cellulose, and can manufacture 



protoplasm. 



Bub-Kingdom Thallophyta, because it possesses neither root, stem, nor leaf. 

 Class Protophyta, because it has no sexual process of multiplication (Gr. prolos, first; plnjton, 



plant). 



A 



