March 9, 1917] 



SCIENCE 



239 



DISCUSSION AND CORRESPONDENCE 



A CULTURE MEDIUM FOR EUGLENA 



A MEDIUM discovered quite by accident has 

 enabled the writer to carry on vigorous cul- 

 tures of Euglena for a period of more than a 

 year. Some five hundred cultures have proved 

 conclusively that it is a success. The medium is 

 quince-seed jelly, which is in common use as an 

 agent for retarding the movements of Protozoa. 

 It is prepared by boiling quince seed in dis- 

 tilled water, passing the thick, glutinous mass 

 which is obtained through a sieve to remove 

 particles of the seed and then diluting with 

 distilled water to the desired consistency. 

 Cultures have been carried in test tubes, jars, 

 flasks and other receptacles. Some tubes re- 

 mained corked throughout the entire year and 

 were found to contain virile cultures at the 

 end of that time. 



The jelly seems to be specific for Euglena, 

 some other chlorophyll-bearing Protozoans and 

 for bacteria. Tubes were inoculated with 

 cultures of mixed Protozoans and after a pe- 

 riod of two months only the Euglena and a 

 minute green flagellate survived, the other 

 Protozoans living only as long as the supply 

 of bacteria lasted. 



Two hundred successful transplants have 

 been made from a single culture. 



The medium has several obvious advantages : 



1. It enables the operator to carry on cul- 

 tures for a long period of time without giving 

 them constant attention. 



2. The medium is viscid and evaporates 

 rather slowly. 



3. A constant as regards density and chem- 

 ical content may be obtained for experimental 

 work by evaporating the medium to dryness 

 and making up a standard solution with dis- 

 tilled water. 



The results of a year's experiments together 

 with some notes on the behavior of Euglena 

 are soon to be published. 



Clarence L. Turner 

 Department of Anatomy and Biology, 

 Marquette University School op Medicinb 



a relief map of the united states 

 To THE Editor of Science: The article en- 

 titled " Expedite the Map," which appeared in 



the October 13 issue of Science, brings to mind 

 the desirability of having in the city of Wash- 

 ington, suitably housed, a large scale relief 

 map or model of the United States. 



This model might be about 300 feet square 

 or 600 feet square, according to the structural 

 difficulties which would be encountered and 

 the amount of appropriation which could be 

 obtained from Congress or other source. 



As to the appropriation, I doubt that it 

 would be easy to secure funds from Congress 

 for an object of this kind, and I believe that 

 it would be better to depend upon private 

 philanthropy to secure the financial founda- 

 tion needed. 



The statement " Every industry, art and 

 science which demands a knowledge of the lay 

 of the land is benefited by good maps of the 

 area in which it is carried on," and the re- 

 mainder of the paragraph from which this 

 sentence is quoted apply equally to a relief 

 map. 



Such a map, if constructed, would be avail- 

 able for consultation by members of Congress, 

 bureau officials and by the general public; and 

 it would be one of the sights of the national 

 capital. The main problem is to find th* 

 philanthropist. T. W. Kinkaid 



leidt on the cause of malaria: a 

 correction 



In a. letter to Professor Henry Fairfield Os- 

 born, published by him in his " Biographical 

 Memoir of Joseph Leidy," ^ I stated that in 

 1853 Leidy " discussed the cause of malaria 

 and wrongly concluded that it is not of para- 

 sitic origin." Dr. Joseph Leidy, 2d, has kindly 

 called my attention to my regrettable blunder. 

 What Leidy really said" was: 



That malarial and epidemic fevers have their 

 origin in cryptogamie vegetables or spores requires 

 yet a single proof. If such were the caae, these 

 minute vegetables and spores, conveyed through the 

 air, and introduced into the body in respiration, 

 could be detected. 



Frank E. Lutz 



1 National Acad. Sci., Biographical Memoirs, 

 VII., 1913, p. 356. 



2 Smithsonian Contrib. Knowledge, V., 1853, p. 

 14. 



