117 



Satavai). The independent rediscovery of these f acts by Winge 2) 

 has recently opened quite new and fundamentally important pros- 

 pects for the study of yeasts 3). 



The next investigation in the yeast domain appeared ten years later 

 and is of mainly physiological interest 4). In this pubHcation the 

 agglutination of yeast cells was discussed. It was pointed out that 

 there are several yeast types showing the phenomenon of auto- 

 agglutination. Other strains, however, hke the ordinary baker's 

 yeast and the top yeasts of breweries do not have this property, but 

 they can be induced to agglutinate by the addition of special types of 

 lactic acid bacteria, as was first observed by Barendrecht 5). 

 Prescriptions for the Identification and isolation oi these bacteria were 

 given. The paper is also of interest because it gives several details 

 regarding the wild yeasts occurring more or less regularly at that 

 time in commercial baker's yeasts (Saccharomyces fragans , S. curvahis, 

 S. muciparus, S. disporus). Finally a method was devised for the 

 quantitative determination of bottom yeast in a mixture with 

 baker's yeast. This method, which depends on the specific abihty of 

 bottom yeast to attack melibiose, has not received due consideration 

 until recently. 



In a short note published in 1913 Beijerinck brought forward 

 experimental proof that the then current procedure for discriminating 

 between living and dead yeast cells with the aid of methylene blue is 

 liable to lead to confusion if applied to yeast dried at a low tempera- 

 ture 6). It was shown to be possible to obtain preparations in which all 

 cells, though staining a deep blue on addition of the dye, still 

 maintained their viability as could be proved by making them ger- 

 minate under suitable conditions. 



About the same period, a study was made of the factors determining 

 auto-fermentation in yeast ''). Beijerinck concludes from his ob- 

 servations that all factors which are harmful for the yeast cells lead to 

 auto-fermentation; this point of view lured him on to some highly 

 speculative ecological considerations. 



In a joint publication with J. J. van Hest «) experiments were 

 reported dealing with Lebedeff's maceration juice. The paper is 

 mainly of interest because in it Beijerinck emphatically opposed 

 the view, current at that time, that zymase was nothing but a definite 

 chemical compound present in the dissolved state in the yeast cells 

 and endowed with the property of splitting sugars into carbon dioxide 



1) K. Kruis and J. Satava, O V^voji a Klfceni Spór Jako2 i Sexualitë Kvasinek. 

 V Praze, 1918. 



2) Ö. Winge, C. R. Trav. Lab. d. Carlsberg, Sér. Physiol. 21, 77, 1935. 



3) Cf. Ö. Winge and O. Laustsen, C. R. Trav. Lab. d. Carlsberg, Sér. Physiol. 22, 

 99, 1937; Ibid. 22, 235, 1938; Ibid. 22, 337, 1939; Ibid. 22, 357. 1939. 



*) Centralbl. f. Bakt. u. Parasitenk. II, 20, 641, 1908. 



5) H. P. BARENDRECHT, Centralbl. f. Bakt. u. Parasitenk. II, 7, 623, 1901. 



«) Proc. Kon. Akad. v. Wet. Amsterdam 21, 930, 1913. 



7) Livre jubilaire Henri van Laer, p. 128, 1913, 



») Folia Microbiologica 4, 107, 1916. 



