SELECTED PAPERS 



proposals for bacterial classification put forward after 19 10. It is true 

 that we still are far from an in all respects satisfactory system, nor can 

 we hope that such an aim will ever be attained. But nevertheless, it 

 can be stated that the phylogenetic approach to the solution of this 

 problem which Stanier and Van Niel have brought in their recent 

 study, has thrown a clear light on the interrelationships of the main 

 bacterial groups, and their place in the natural kingdom. And it 

 seems likely that a future more detailed system will be based on the 

 same judicious balance in the evaluation of both morphological and 

 physiological properties which is characteristic of the study of the 

 American authors. 



A second feature of the tendency to bring order into the world of 

 microbes has been the foundation of several institutions where collec- 

 tions of living micro-organisms have been brought together and are 

 maintained. As such mention may be made of the 'Centraalbureau' 

 for cultures of fungi, including yeasts, founded already in 1906 in my 

 own country, the National Collection of Type Cultures established at 

 the Lister Institute in London, the American Type Culture Collection 

 formerly in Chicago, now in Washington, and the new, economically 

 very important collections of moulds and yeasts established in the 

 Northern Regional Research Laboratory at Peoria (111.). Moreover, 

 several scientists who have been specializing on certain groups have 

 maintained private collections, and it should be mentioned here that 

 investigators in demand of cultures of lactic acid bacteria will seldom 

 have appealed in vain to Orla-Jensen's generous cooperation. 



It seems certain that collections like those mentioned serve several 

 useful purposes. In the first place they promote the dissemination of 

 knowledge by providing scientists all over the world with authentic 

 cultures of organisms discovered or described by their colleagues else- 

 where. Secondly these institutions often develop into centres where 

 special groups of organisms are more or less exhaustively studied from 

 both a systematic and a physiological standpoint. This not rarely leads 

 to the publication of monographs dealing with such groups, of which I 

 need only mention Orla-Jensen's two volumes dealing with 'The 

 Lactic Acid Bacteria' in order to impress the importance of such stud- 

 ies upon you. 



Looking back once more into the post-explorative era of microbiology 



372 



