124 



Scientific Proceedings (53). 



Galvanotropism, which has so far eluded observation in Euglena 

 was obtained by using culture media containing citric acid. With 

 this material it was found that the method of orientation is 

 identical in both galvanotropism and heliotropism. Consequently 

 the orientation to light is as direct as the locomotor mechanism 

 of Euglena permits, and does not take place by "trial and error." 



81 (777) 



The fat content, morphology and length of life of cells growing in 

 diluted blood plasma. 



By Robert A. Lambert. 



[From the Department of Pathology of the College of Physicians and 

 Surgeons, Columbia University.] 



Cells growing in unmodified blood plasma (Harrison's 

 method) exhibit regularly an accumulation of fat droplets in their 

 cytoplasm. In the case of the cells of the chick embryo this fat 

 accumulation is quite marked after 24 to 48 hours, and reaches a 

 maximum after five to seven days, at which time the cells are 

 distended with fat droplets. 



The experiments herewith reported were planned to determine 

 the effect of a reduction in the fat content of the culture medium, 

 brought about by dilution of the plasma, on the accumulation of 

 fat by the cells. In the course of the experiments the influence 

 of dilution on the length of life and morphology of the cells was 

 also observed. 



One part of plasma added to twenty or twenty-five parts of 

 Ringer's solution forms a medium which coagulates satisfactorily 

 in hanging drops. Studies were made with dilutions of 1:2, 

 1:5, 1 : 10, 1 : 15, and I : 20 of pigeon plasma in Ringer's 

 solution, containing 0.9 per cent. NaCl. Pieces of chick embryo 

 heart were used for cultivation. The tissue was finely divided 

 into pieces of suitable size for cultures, which were washed in 

 Ringer's solution for a half hour before using. Cultures from the 

 various series were fixed in formalin at the end of two, three and 

 four days and stained with hematoxylin and Sudan III. 



The results may be briefly summarized : 



