> 



7G 



medium About one hour al'lcr llic pi'cparalioii ol' llic cul- 

 lui"i\ an oulliiic (Irawinij; was (faced under llie |)i'()jecl()- 

 sc'oix'. Ariel l«S liours incubalioii llie oidliiie ol' llu' new 

 growlh was drawn ol' llie control and the ex|)erimenlal 

 cuilurt'. and calculalions were made hy Ihe melliod dc- 



13 



12 

 II 



10 

 9 



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 



Passage 



Fig. 7. 



The growth of the four cultures of the experiinents expressed 



graphically. 



scribed in the beginning of Ihis chapter. At each passage 

 the culture was divided into two parts. One IVagnient was 

 kept as control and the oilier placed in the experi menial 

 medium, care being taken to keep Ihe other factors con- 

 slant, such as the osmotic pressure and so on. 



The curve ()i)lained for the rale of growth of fibro- 

 blasts cultivated in media containing different hydrogen ion 



