ABSORPTION OF AMINO- ACIDS 85 



More recent experiments have served to emphasize that 

 the previous history of the cells and the presence of other 

 amino-acids profoundly influence the inward as v^ell as the 

 outward migration of lysine and glutamic acid. Cells con- 

 taining only lysine in large amounts were obtained by 



50-1 



4-0- 



3-0- 



«/)2-0- 



r20 



-16 



hi2 



d 



z 

 o 

 o 



z 

 cr 



1 £- ^ 



EXTERNAL CONG. (/* mole/m.l.) 



?i 



-4. 



20 



FIG. 6.2. — Effect of external concentration of lysine on (a) internal 

 concentration of lysine (#) and (b) the ratio of internal con- 

 centration of lysine to external concentration: in ratio calcu- 

 lations internal concentrations expressed in terms of volume 

 of intact cells (A) and volume of intact cells less that of solid 

 debris (^). Strep, faecalis suspended in lysine solutions for 

 3 hr. at 4° C. [5] 



incubating a washed suspension of amino-acid deficient 

 cells in the presence of lysine [16]. When these cells were 

 transferred to an amino-acid free environment (o'i5 M.-NaCl 

 or Na2HP04 at 37° C.) lysine migrated out into the sur- 

 rounding medium and, in contrast to the previous experi- 

 ments with amino-acid rich cells, the migration occurred in 



