ISN 



Tlu' sijfiiiricMiU'c ol" Ihc ci'lluhir anastomosis, round in llic 

 lissiu' c'ulliiro. is slill heller (Iciiionsli-ali'd in Iho expeiMnienls 

 wilh llu' |)ulsalin<^ rra«»nu'nls ol' lu-arl in vilro. 11 was I" ound. 

 Ihal two rra<:;nu'nis of |)iilsalin,ij; lu-aii lissiic, cillu'r IVoin Ihc 

 same liearl or from dinci'cnl hcaiMs ol' llie same species, 

 \v(MH' ahle lo reunite and Ihe two pieces cslahlishcd one 

 simuUancousIy pulsalinjf nnil. II was ohscrved, Ihal wlien 

 no simullaiieily ol" two IVa^Mnenls could i)e ohtaiiicd. no 

 hislol()<«icaly deleclahk' pi'olo|)lasmic connection hetween 

 Ihc contractile elemenls of Ihe two Iragmcnls could he seen. 



3. INTERACTIONS OF TIN-: TISSL K ("ELLS IN \ITR(). 



l-'rom ex|)i'rinu'nls on ri'gcneration ol' certain lower ani- 

 mals, it is known how parts separated from tlu' hody are 

 able lo develoi) and form a j)erfect organism. It is slated 

 that it is the se])aration or isolation of the i)art from the 

 influence of Ihe organism as a whole, which initiates the 

 process of regeneration. 



It has been further shown that if certain organized tis- 

 sues as kidney, thyroid and skin, for instance, are cxplanled 

 and allowed to grow for some length of time in cultures, 

 the tissues looses its characteristic architecture and one lyi)e 

 or another of the cells grow out from a tissue without any 

 regular organization, (C h a m p y) ^-^y 



At other times the gi'owih of the explanled complex tis- 

 sue is controlled and continues to grow as such. This is de- 

 monstrated by T h o m s o n '='•') and Fischer i'"^). T h o m- 

 son observed, that if a toe from a chicken embryo was 

 explanled. an uncontrolled ju-oliferalion of cells began from 

 Ihe injured ])arts. lie slated, that when Ihe basal membranes 

 are injured, the cells commence growing out into Ihe me- 

 dium, whereas an uninjured organ continues to grow as a 

 complete structure, controlled by Ihe laws of the organism. 

 This does not seem to l)e a constant jjhenomenon; it was 

 observed (Fi s ch e r) i^^) that small fragments of intestine 

 from Ihe chicken embrvo did not \vv\ often exhii)it anv 



