^g^ REGENERATION AND GROWTH 7 



decline in regenerative power begins early, soon after the stage of 1 1-14 somites 

 in the chick (Zwilling, 1942). 



The relationships and interactions between regeneration and abnormal can- 

 cerous growth have been studied. Skin regenerates more slowly near a grafted 

 tumour than elsewhere (Zdriukovskaja, 1942), but the presence of regeneration- 



n 

 Fig. I . Parasagittal section through 

 the anterior abdominal region of an 

 adult male Asellus aquaticus showing 

 the extent of fusion between a graft 

 of tissues from an embryo and the 

 adjacent normal and regenerating 

 tissues of the host. The embryo- 

 tissues are somewhat disorganised as 

 a result of the procedure of grafting 

 but there is no certain evidence of 

 qualitative interaction between the 

 three types of tissue. An infection of 

 the host tissues (small dark spheres) 

 has not affected those of the embryo, 

 at any rate in the time available. 

 There appears to be a tissue-barrier 

 between embryo and host body- 

 cavities. 



A: anterior, AH: abdomen of host, BCE: body cavity of embryo, BCH: body cavity of 

 host, BCSH: base of copulatory style of host, D: dorsal, HDH: hepatic diverticula of host, 

 HGE: hind-gut of embryo, JEH: junction between embryo-tissues and normal host 

 tissues, JER: junction between embryo-tissues and regenerating tissues of host, P: posterior, 

 PH: pleopods of host, R: regenerating anterior abdominal appendages of host, V: ventral. 



activity in the liver of the rat facilitates the induction of tumours (Glinos et al., 

 1950). The apparent paradox again may prove to depend on the relative timing 

 of the two processes. These quantitative interactions seem to contrast with a num- 

 ber of records of qualitative, organisational indifference between the two types 



AHI 



TABLE 3 



EVIDENCE CONCERNING QUALITATIVE INTERACTION BETWEEN TISSUES OF 

 DIFFERENT MORPHO GE NETI C TYPE, WHEN APPROXIMATED BY GRAFTING 



Type of tissues approximated 

 Regenerating and cancerous 



Regenerating and embryonic 



Regenerating and mature 



Indifference recorded 



Interaction recorded 



Peredelsky, 1941 

 Breedis, 1954 

 Ruben, 1955 



Emerson, 1940 

 Needham, 1950a 



Rose and Wallingford, 1948 



Umanski, 1933 



Schotte, 1937; Schotte and 



Hummel, 1939 



Waddington, 1940 Trampusch, 1951; 

 Hubl, 1 95 1 Gebhardt, 1926 



Ruben, 1955 Morphallaxis, generally 



