A New Culture Medium for Protozoa. 



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A new culture medium for Protozoa. 

 By Rh. Erdmann. 



[From the Osborn Zoological Laboratory, Yale University.] 



Although there are many media extant for cultivating try- 

 panosomes in test tubes, a satisfactory medium for culture on a 

 slide under a cover glass has hitherto not been described, in spite 

 of the fact that only by the slide method is it possible to study the 

 sequence of changes with the greatest accuracy. The method 

 here outlined makes possible the continued study of the life history 

 of the organism either in prepared culture medium or in inoculated 

 tissue. 



As a culture medium the plasma of the host is employed and 

 this is either inoculated with the trypanosomes themselves or used 

 as a medium for the growth in vitro of various infected tissues 

 of the host. I have used the plasma of the rat in studying the 

 development of Trypanosoma brucei and have been able to keep 

 the trypanosomes in a normal condition for an indefinite period 

 whereas by the use of Ringer's fluid or blood bouillon the organisms 

 die after a few days. 



The plasma was obtained by the method of Harrison, 1 Burrows, 2 

 and Walton, 3 the latter making adaptations for mammalian plasma. 

 In brief, the blood from the infected rat was taken and put into a 

 small drop of plasma on a cover glass and then this was further 

 diluted with plasma in order to reduce the number of blood cor- 

 puscles in the hanging drop which was taken from this. The cover 

 glass with hanging drop was either placed on a depression slide or 



1 Harrison, R. G. Observation on the living developing nerve fiber. Proc. 

 Soc. Exp. Biol, and Med., 1907, Vol. IV, p. 140-46. The outgrowth of the nerve 

 fiber as a mode of protoplasmic movement. Journ. Exp. Zool., 1910, Vol. IX, 

 p. 787-848. 



2 Burrows, M. T. The cultivation of tissues of the chick embryo outside the 

 body. Journ. of the Amer. Med. Ass., 1910, Vol. LV. The growth of tissues of 

 the chick embryo outside the animal body, with special reference to the nervous 

 system. Journ. Exp. Zool., 191 1, Vol. X, p. 63-83. 



'Walton, A. J. Variation in the growth of adult mammalian tissue in 

 autogenous and homogenous plasma. Proc. R. S. L., Ser. B., Vol. 87, p. 452-61. 



