38 



gators. The surface ol' :i li(|iii(l is siilTicicnl support for 

 the nii<*ralion of cells This |)lu iioiucruui can he sccu very 

 often whih workiuL* with lissue <'nllures. II vaw he seen 

 how tissue cells ai"e ahle to i^i-ow on the \'rvv suiiace of 

 the licjuid. 



The growth of tissue cells is closely coniiecled \\itli 

 surfaces, and the fihrin clot can therefore he considei-ed as 

 an enormous surface of tlu' fihrin c'ox'ered willi a thin lilni 

 of li(juiil i)y means of ca|)illary suction. 



In some other e\|)erimenls I tried elderherry |)ith as a 

 support U)V llie gi-owth of fihrohlasls. 'j'hin (hscs of the 

 pilli were l)r()uglil to float in the licphd emhryouic lissue 

 juice and the lissue fragment was |)laced on this moist 

 surface, (irowth look place on this surface (piile extensively 

 and tlie disc* was removed from the tissue juice after l<S 

 liours in tlie incul)alor. washed in Ringers solution and 

 made to float again on fresh juice. In this way the tissue 

 could be kept alive foi- a long period nu'rely by changing the 

 liquid medium. In llie meanlinu' the pith did not prove 

 to be very good h)r microscopic examinalions; it had to 

 be sectioned and stained if it was to be subjected to a 

 tliorough microscopic examination. The utility of this method 

 would, perhaj)s, be found when it is necessary to grow 

 tissue on the same suj)porting apparatus for a long period 

 to study a possible changing organization during a con- 

 stant renewal of the nourishing aiid gr!)wlh-|)romoling sub- 

 stances. 



Oilier malei'ials hax'c been tried as frame work for the 

 lissue growth. II a r r i s o n 251) used spider-web; (barrel 

 used silk gauze and hair and I have used ordinary adsorbent 

 cotton. All these substances can he successfully used as a 

 framework hul the outgrowth always de|)en(ls on the pri- 

 mar}' contact between the tissue fragment and Ihe material. 

 For a quantitative study of the rate of growth these sub- 

 stances cannot very well be used because of tlie many in- 

 cidental errors. 



