APPENDIX A. 



YEASTS AND MOULDS. 



Yeast-fungi and mould-fungi, like bacteria or fission- 

 fungi^ are achlorophyllous TJiallopJiytes. They belong to 

 two separate orders, the Saccharomycetes and HypJiomy- 

 cetes, which are intimately related to each other, but quite 

 distinct from bacteria. Their germs occur widely dis- 

 tributed in air, soil, and water, and are constantly en- 

 countered in bacteriological investigations. In addition 

 many species are of hygienic and pathological interest or 

 importance in being either accidentally associated with, 

 or actually the cause of various morbid processes. For 

 a complete account of all the described species and full 

 details of the various forms of development,* reference 

 must be made to botanical treatises. A description of 

 certain species is appended here, and may afford some 

 useful information to the worker in a bacteriological 

 laboratory. 



YEAST-FUNGI OR SACCHAROMYCETES. 



Saccharomyces cerevisiae (Tonda cerevisice). 

 Cells round or oval, 8 9 p long, singly or united in 

 small chains. Spores occur three or four together in a 

 mother-cell, 4 5 JJL in diameter (Plate XXIX., Fig. 2). 



Sacch. ellipsoideus. Elliptical cells, mostly 6 ^ 

 long, singly or united in little branching chains. Two to 



* Sachs, Text-book of Botany. 1882. 



