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X.— THE TECHNIQUE OF CULTURING 

 AMCEBA PEOTEUS.* 



By Monica Taylor, S.X.D., D.Sc, and Catherine Hayes, S.KD. 

 (Communicated by Professor J. Bronte Gatenby, F.E.M.S.) 



(Read June 15, 1921.) 



The desirability of placing our experience of four years' successful 

 work in some permanent and easily accessible form has been 

 insistently emphasized by our reception of many letters asking 

 for cultures, or for advice on the method of starting these, and 

 maintaining them under varying conditions. Hence this ISTote, 

 in which w§ have also endeavoured to give (in the subdivision, 

 " Some Exigeucies and How to Meet Them ") a general answer to 

 the questions most commonly asked of us in connexion with the 

 Technique of Culturing Anueba ])roteus. 



For convenience of reference we give at the outset, in a some- 

 what tabular form, the following list of what is requii-ed for the 

 cultures : — 



Glass vessels, rectangular (about 8 in. by 6 in. by 4 in.) or 

 cylindrical (diameter 8 in., height 4 in.) ; glass covers for these. 



A supply of boiled wheat grains (boiled to kill the embryo, 

 which might otherwise germinate) ; 22 grains to a litre of liquid 

 is a rough estimate of the amount of wheat required. 



A Zeiss binocular microscope, or a dissecting microscope, or a 

 mounted lens. 



Boiled rain water, if the tap water is inimical. The cultures 

 thrive best near a window at a temperature of 54° F. to 60° F. 



Establishment of a Culture. 



With regard to the establishment of a new culture, the quickest 

 method for us, where our cultures have been thriving steadily for 

 years, is, obviously, to sub-divide an already existing one. When 

 despatching such a sub-culture to another laboratory we find that 

 the following instructions have proved of use to the recipient, who 

 in most cases has been successful in establishing permanent sup- 

 plies : — " Add three or four times its volume of water to the 

 enclosed quantity of the original, and a supply of wheat, this latter 

 to be regulated by the bulk of the culture. 



* The species dealt with is A. proteiis Pallas (Leidy). See Literature List. 



