6 



THE AMERICANN MONTHLY 



[Jan., 



a small glass of dilute alcohol. According to a recent 

 communication by Effront, squares of clay may be used 

 instead of the gypsum. The form of the substratum is 

 immaterial. 



Cultivation in sterilized water in a test-tube, or on 

 moistened filter-paper, will — ceteris paribus — result in a 

 formation of spores in the yeast. Eor the determination 

 of species, the method described above must be recom- 

 mended, because it is one of the factors in Hansen's es- 

 tablishing of his species. It is still an open question 

 whether the different ways of spore-cultivation affect 

 the results in regard to the time, at constant tempera- 

 tures, in which spores are formed. — Other points, con- 

 cerning spore-cultivation of pure cultures, will be men- 

 tioned below. 



Remarks on the spores. — A table above indicates the 

 results and how to use them. The spores are, in the cul- 

 tivated forms very refractive compared with those of the 

 wild forms*. Their size and number varies somewhat : 



KINDS OF YEASTS. 



1. S. cerevisiae I 



2. S. pastorianus I.... 



3. S. pastorianus II... 



4. S. pastorianus III. 



5. S. ellipsoideus I 



6. S. ellipsoideus II... 



7. S. marxianus 



8. S. exiguus 



9. S membrantefaciens 



10. S. ludwigii 



11 S. anomaliis 



[All of Hansen.] 

 12. S. hansenii Zoph 



Spores. 



Dia. 



2,5-6 

 1,5-5 

 2-5 

 2-4 

 2-4 

 2-5 

 2-4 

 2-4 



No. 



1-5 



1-10 



1-7 



1-10 



1-4 



1-4 



2-3 



1-8 

 2-4 



Spores. 



KINDS OF YEASTS. 



Dia. 



No. 



13. S. joergensenii Las-| 



Che I 1-2,5 



14. S. c o n g 1 omeratusj 



reess 1 



15. S. albicans Reess ..\ 



16. S. Reessi David.... 



17. S. galacticola Perot. 



et Rib 



18. S. I. of Will 



19. S. II. of Will 



20. S. minor Engel 



21. S. ilicis Groenld.... 



22. S. aquifolii Groen. 



2-4 



1,5-5 

 2-4 

 3 



1 

 3 



2-4 

 1-5 

 1-4 

 2-4 



*Wild forms is an expression nbw commonly used of the forms that are not 

 cultivated. This term is intimately connected with the post-pasteurean view 

 of these plants, and with the question of pure cultures and of pure yeast. 

 pure cultures, such as we know them to-day, were not known to Reess (1870") 



