278 



PRINCIPLES OF EMBRYOLOGY 



of intrinsic and extrinsic factors in the architecture of the skeleton has been 

 discussed particularly by Murray (1936). The development of Hmbs in 

 abnormal sites in the body has provided the opportunity for a large 

 number of investigations on the way in which the peripheral nerves make 

 contact with the various parts of the limb, and also on the influence of an 

 excess or deficiency of peripheral organs on the central nervous system 

 There is no space here to do more than mention this subject as one which 



Figure 12.14 



The development of a limb-bud of the chick, transplanted to the coelome 



and badly innervated {h), compared with that of a normal limb {a}, (brom 



Hamburger and Waugh I940-) 



provides evidence of epigenetic interactions between parts of the body 

 continuing into the later stages of development. Recent reviews of the 

 field will be found in such works as Piatt (1948), Weiss (1941, I950^) and 

 Detwiler (1936). 



SUGGESTED READING 

 Classical papers are Harrison 1918, 1936, 1945; and Spemann's work on the eye. 

 summarised 1938, pp. 40-97- For a general survey of experimental work on Amphibia, 

 Needham 1942, pp. 290-309; on the chick, Waddington 1952^, PP- 140-200, ^d Annals, 

 Net. York Academy of Science 1952, Volume 55, Article 2. Two very interestmg Imes 

 of work, hardly touched on m the main text, will be found in Rawles 1948 and Landauer 

 1954- 



