Parameciidae 127 



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1934- Turtox News 12:127. 



Lund, Barbara L. 1918. Biol. Bull. 35:211. 



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CULTURING PARAMECIUM CAUDATUM IN OAT STRAW 



INFUSION 



George A. Smith, Eugenics Record Office 



AN EXCELLENT medium for culturing Paramecium caudatum for 

 JL\ a rapid population growth is an oat straw infusion. After having 

 experimented with various types and concentrations of culture media 

 made from timothy hay, oat straw, barley straw, oak leaves, elm leaves, 

 clover, alfalfa, etc., oat straw was found to be the most favorable medium 

 for rapid growth of my strain of Paramecium. 



Cut 15 grams of oat straw into short lengths (1-3 cm. long) and place 

 in a quart glass container. Pour 900 cc. of boiling distilled water over 

 the straw. Plug the container with cotton and allow the mixture to cool. 

 Adjust the pH to 7.8 with NaOH. The colorimetric method is sufficiently 

 accurate. Keep the mixture at approximately 25 C. temperature for 

 48 hours. Shake the culture medium until it is thoroughly mixed; again 

 adjust the pH to 7.8 and the infusion is ready to use. Add approximately 

 250 Paramecia and in a few days a mass-culture should have developed. 



For best results make new culture medium every 48 hours and make 

 new inoculations as often, because usually after 72 hours have elapsed 

 the culture medium begins to deteriorate and is not at its best for op- 

 timum growth. 



By following the above procedure a number of times a colony of 

 rapidly dividing Paramecium caudatum can be developed, each animal 

 dividing at an average rate of once every 8 hours. This is considered 

 optimum growth under these conditions. 



For culturing animals for classroom use put two or three dozen grains 

 of oats in 1,000 cc. of water and allow the mixture to stand for three 

 days before inoculating with Paramecia. Within a week a mass-culture 

 of the animals usually develops. It is best to keep the culture covered 

 when it is not in use. 



Reference 



For the culture of Paramecium caudatum see also pp. 56, 105, 113, and 119. 



