71 



I'lihilr readily wliicli IjunVr slioiild be used lo produce 

 Ihr hydroj^U'ii ion coiiccnlralioii desired in liie lissiie juice 

 (fig. 3). 



Iloreidler il was necessary lo make anollicr lest in the 

 same way, namely willi lln' plasma-lissue juice mixliire. 

 This had lo I)c done rapidly in order lo mix indicator 

 and juice-plasma helore coaj^ulalion look place. In olher 

 words, when fibroblasls are lo be cullivated in a medium 





U 



8 



5 6 7 



pH 



Fig. 5. 

 The different hydrogen ion concentrations of the media in which the first 

 passage of the old strain of fibroblasts is cultivated are indicated by the 

 abscissae. The ordinates indicate the relative increase of growth. Phosphate 

 buffer solutions were used. 



of, lei us say, Pli (>. preliminary expcrimenls lor those 

 particular media will show what buffer solutions should 

 be added to the juice which will give Ph 6, when combined 

 wuth plasma. The test should be made in two steps for 

 each experiment, one for the juice-buffer, and the other 

 foi' the juice-buffer-plasma mixture, because of the slight 

 differences in hydrogen ion concentration of the different 

 juices and plasmas. The embryonic tissue juice may vary 

 from Ph 6,8 to 7,2, and the plasma from Ph 7,1 to 8,0. 



