ALGAL CULTIVATION PROBLEMS 15 



phyta will be discussed in a later portion of this paper, but this 

 leads me to an important aspect of my topic — : how can such 

 pure- or at least uni-algal cultures be preserved for future use in 

 taxonomic work? Again we are lagging behind the bacteriolo- 

 gists and even the mycologists who have maintained for many 

 years a collection of type cultures. Dr. Pringsheim's collection 

 formerly at Prague and now at Cambridge, the collection now 

 located at Charles University in Prague and the Bourrelly cul- 

 tures in Paris represent the European collections. From corres- 

 pondence with Dr. Pringsheim there seems to be doubt that his 

 collection will long survive him, and present conditions in Czech- 

 oslovakia are not encouraging. It seems to me, as has been sug- 

 gested previously by members of this Society, that it is our respon- 

 sibility somehow to establish a permanent collection of pure cul- 

 tures of living algae in this country. With the current great in- 

 crease in use of algae for genetical and physiological studies both 

 by private investigators and government research establishments,, 

 some financial support and encouragement for such a project 

 must be possible. 



The remaining "problems" involved in or related to the culti- 

 vation of algae, to which I shall now turn my attention, are more 

 in the nature of "sins of omission" rather than some of the taxo- 

 nomic "sins of commission" we have just reviewed. There prob- 

 ably is not available such an assemblage of plants as favorable 

 as the algae for providing so many investigators with challenging 

 opportunities for research. The writer has several times interro- 

 gated plant physiologists as to whether normal, metabolically 

 active algal cells secrete into the surrounding medium some of 

 the sugar presumably formed during their photosynthesis. Their 

 responses have been vague and indicate lack of pertinent data. 

 This is a question of fundamental importance for, inasmuch as 

 we know from the work of Moewus and Kuhn that more com- 

 plex compounds are actively secreted by healthy algae, on theo- 

 retical grounds there is no reason why one should not expect 

 some diffusion of photosynthate into the external medium. If this 

 does occur it is a factor which has been largely overlooked in 

 limnological and ecological studies of microorganisms; if it does 



