57 



c'C'plion of llu' blood coal. Both series of test lubes, experi- 

 ments and controls were placed in the incubator at 39 C. 

 for one hour and shaken evi'ry 10 minutes. Hereafter they 

 were placed in the refrigerator over night. The following 

 morning the solutions were centrifuged, the supernatant; fluid 

 drawn off and the hydrogen ion concentration adjusted for 

 all of them to Ph. 7.0. l)y adding various amounts of n/tO 

 HCl or XaOII, an amount which was found empirically. 

 After this neutralization, the solutions were ready to add to 

 the culture media and the rate of growth determined. The 

 tissue used as a reagent was the then 9 years old strain of 

 fibroblasts in the Rockefeller Inslitiile. As usual only good 

 cultures were used for the experiments. The tissue fragment 

 was cut into two halves, the one served as control and the 

 other for the experiment. The control contained one volume 

 of plasma and one volume of the tissue juice-buffer mixture 

 which previously was neutralized to Ph. 7,0, i. e. having 

 been treated in the same way as the experimental extract, 

 with the exception of the adsorbent. The experimental cul- 

 ture contained one volume of the supernatant fluid from 

 the blood coal, after of course also having been neutralized 

 to Ph. 7,0. and one volume of plasma. The method for quan- 

 titative estimation of the rate of growth was the usual as 

 often before described. ^^^). 



It has been endeavoured to see if it was possible to 

 remove a part of the adsorbed substances from the adsorbent, 

 and especially in the cases where a marked adsorption of 

 active substances has taken place. 



It has been shown, that antibodies which had once com- 

 bined with adsorbent or homologous antigen, can be removed 

 from their attachment and rendered reavailable. F. H u n- 

 t o o n 267 - 268) j-j^j^ sludicd the conditions under which the 

 dissociation of antibodies takes place. He declares, that 

 antibodies are bound to the antigen in all different grades of 

 stability, from that part which is very loosely bound and 

 easily washed out. He found, that the dissociation was very 



