THREE DECADES PROGRESS IN MICROBIOLOGY 



known that he feared that such praise might lead to relaxation, in- 

 stead of acting as a stimulant to further efforts. 



But, nevertheless, I venture to think that in his heart a feeling of 

 satisfaction would not be lacking. In the first place this seems to be 

 most probable, when we remind ourselves of the fact that during his 

 life-time Hansen had to devote part of his energy to the defence of the 

 view that the yeasts which he brought together in the genus Saccharo- 

 myces have to be considered as independent forms of life, and not, as 

 was repeatedly suggested, are mere stages in the life cycle of higher 

 fungi. Seen in this light Hansen would have relished in the present 

 situation in which about ioo different ascosporeforming yeast species, 

 divided over 15 genera, are generally accepted as independent organ- 

 isms in the botanical world. Moreover, he might have rejoiced at 

 seeing that attempts to deal in a somewhat comprehensive way with 

 the systematics of yeasts, of which systematics the foundations were 

 laid by him, have necessitated the publication of three more or less 

 stately volumes. 



In view of his great devotion to the industrial applications of yeasts, 

 Hansen would also have been interested to see that the organisms 

 which are undoubtedly responsible for the particular qualities of spe- 

 cial types of English beers continue to receive the attention of scientists 

 of the small nations. Herewith I refer to the remarkable group of 

 yeasts first discovered and described by your fellow-countryman Hjelte 

 Claussen, and to which the name of Brettanomyces was given by him. 

 Later on they have once more been most thoroughly studied in Copen- 

 hagen by Schionning, and I am glad to be able to add that my collab- 

 orator Custers of late could prove that British conservatism has con- 

 tinued to safeguard during another 40 years the hospitality offered by 

 British breweries to a group of micro-organisms, the natural occur- 

 rence of which is still wrapped in mystery. 



There also seems no doubt that it would be a source of true satis- 

 faction to Hansen to see that nowadays the industrial application of 

 yeasts is no longer restricted to his two favourite species : Saccharomyces 

 cerevisiae and Saccharomyces carlsbergensis, but that for the production of 

 food yeast, fat or vitamins several other species have been, or are 

 likely to be introduced into industry in a near future. 



But all these minor joys which Hansen might experience, if he was 

 able to inspect his old kingdom, would appear to him as mere trifles 



39i 



