186 



coiilrnclilc ilciiu'iils Ironi llic one fra/^nieiil had c'slal)Iislu'(l 

 a (liix'cl |)r()l()])lasiiiic conlacl wilh llic conlractilc clcim-iils 

 of [hv ollu'i Ira ;4i lit- lit. whereas in Ihe line of conlacl i)clween 

 Iwo Iraj^mciils wliicli had not iiiiiU'd |)li\ siologically, a de- 

 linilc layii of coniicclivc lissiic was inlcrposcd, (ViQ. 41). 

 Two IragiiU'ids of i)ulsatin<^ hcarl Ironi Ihc same species, 

 cullivatod in vitro, are able to unite and pulsate simullane- 

 ously. Tins is |)()ssil)le lor IVa^nienls ol" heart, derived from 

 two dillerent individuals helongiuj^ to the same species, 

 whei'ea-. it was not jiossihle to obtain any physiolojfical uni- 

 tion between a heart rra<4menl Iroin duck embryo and a heart, 

 fragment of a cliicken embryo, though both fragments arc 

 able to pulsate and live unaffected by the culture medium. 

 It was found also that fil)roblasls from duck were able to 

 grow and multi])ly indefinitely in the heterologous culture 

 medium. 



It is an interesting phenomenon, that it is impossible 

 for two fragments of heart, belonging to different species, 

 to unit(> and establish a physiological integrity, though the 

 cell elements of the one species are able to live and multiply 

 indefinitely in the heterologous medium. The culture medium 

 itself does not seem to ])lay any role, but the difference and 

 the cause to the uneslablished unilion lies in the cells 

 themselves. The cellular contact and its function, is an 

 important factor, differing from that played by the sub- 

 stances in the culture medium. If no cellular contact was 

 obtained that could be controlled by the histological examina- 

 tion there was no physiological unilion. i. e. no simidlaneous 

 contraction. 



It can therefore be concluded, that the cellular contact 

 between the contracting elements of the two pulsating neart 

 fragments is the unquestionable cause of the simultaneous 

 pulsation. This is also a direct proof that the cellular contact 

 or anastomosis plays an important role for this and other 

 functions even in the tissue culture. 



