184 



cul in two in Ihc Jilicndy pri'parrd culliirc modium and 

 kept in |)()sili()n tlicrc unlil coa^ulalioii look place. Hy this 

 iiu'lhod a simiilt;iiU()iis pulsation was ali'cady obtained 21 

 iioiirs alter. 



A gt)od many experiments wt-i'i' made, to see if it was 

 possible lo obtain a simidtaneons contraction between two 

 fragments of lieai't, liie one derixcd from a duck embryo 

 and tile other from a chicken enil)r\() I'he helerolo^ons 





Fig. 40. 

 Experiment 206b. A section ttirough the line of contact of two fragments 

 of cliich embryo lieart wtiicli had pulsated perfectly simultaneously in vitro. 

 The contractile elements of the one are in direct contact with those of the 



other. X 175. 

 From The Journ. of Exp. Med., 1924, XXXIX, 577. 



cultnre medinm for the duck heart, namely chicken plasma 

 and embryonic chicken juice, had no influence on the growth 

 of the duck fibroblasts. It has been possible to cultivate 

 duck fibroblasts for as long a j)eriod in chicken medium, as 

 3 months. The growth of the fibroblasts from duck was jusl 

 as intensive as that of chicken fibrol)lasts - and it is pos- 

 sible lo say now, that liu' duck fibroblasts arc able to grow 

 indefinitely in the chicken plasma and embryonic tissue 

 juice from chickens. Therefore it was of great importance 



