()() 



Ihc adsorbonl was t'oiind to \\;i\v no toxic t'lTcct on Ihe 

 growth of fibroblasts. 



RKSULTS. 



Two sets oi" test tubes, 1 in each set were used in an 

 experiment. The one set had blood coal as adsorbent and 

 the other had no adsorl)ent. All Ihe tubes contained 1..") cc. 

 of freshly prepared embryonic tissue juice and 1.5 cc. of 

 a buffer solution which gave the solutions different nydrogen 

 ion concentration. The 1 lubes with the adsorbent have 

 exactly the same Ph. as the 1 tubes without tlie adsorbent. 

 To the number one of each set is added a Ijuflei' solution 

 with Ph. 5,0 and to llu' nundK'r two of each set is added 

 a buffer solution with Ph. 0,0 and so on. The total nitrogen 

 was determined of the supernatant fluid in the set which 

 contained blood coal and of the fluid in the set which did 

 not contain the adsorbent. After the hydrogen ion concen- 

 tration was adjusted to Ph. 7,0, the fluids were added to 

 the culture media and the rate of growth for the fibro- 

 blasts determined. 



It was found that the total nitrogen in the supernatant fluid 

 was reduced to about 10 — 50 percent when lOper cent blood 

 coal was used as adsorbent, whereas the growth promoting 

 activity of the supernatant fluid differed rather much in the 

 various experiments and was not constant at all. It can be 

 summarized in stating, that the growth i)romoting power 

 was least when the adsorption took place at a relative high 

 hydrogen ion concentration; in spite of the after neutrali- 

 zation there remained a permanent change in this |)ortion, 

 namely a less activating power as compared wath that 

 of the other solutions. This permanent change towards a 

 less active power, might be due to the effect of the hydrogen 

 ion concentration and not due to any adsorption, because 

 the same change was observed on the corresponding tube 

 in which no adsorbent was present. Any visible precipitation 

 could not be observed in the fluid without adsorbent. 



