EYE FIELD OPERATIONS 



PURPOSE ■• To determine the anlage for the optlco-ocular apparatus; the limits of regenera- 

 tion of parte of the eye field; the time and extent of self-differentiation; the induc- 

 tive relations; and the extent of experimentally induced cyclopia. 



MATERIALS : 



Biolopjical : Anuran emhryos stages #7 to #17; Urodele embryos stages #11 to #50. 

 For heteroplastic transplajitations, use: 



Eana: cateshiana, paluatris, pipiens, and sylvatica. 

 Amblystoma: punctatum and tigrinum. 



Technical : Standard operating equipment. 



METHOD: 



Precautions : 



1. It is Important that the student hecome thoroughly acquainted with the normal 

 development of the eye. This may be accomplished by dissecting living and pre- 

 served embryos at the stages listed above. 



2. The usual precautions must be observed for operations (see section on "Wound 

 Healing" ) . 



5. The optimum temperature at which to rear the operated embryos differs for the 



Anura and Urodela. For the Anura the range is 18°C. to 25 C. and for the Urodela 

 it is about 12°C. to 18°C., depending upon the species. 



Control 



For the excision, cauterizing, transplantation, and regeneration experiments 

 the controls will be different. In many instances the untouched (bilateral) aide 

 may be considered as the control. 



Procedure: 



PRELIMINARY STUDIES ON THE EYE FIELD 



It is necessary to give here a brief description of the topography of the eye-forming 

 materials. This is made possible largely by the work of Vogt (I929) in his classical 

 paper on vital staining and mapping of anlagen, from Woerdeman (I929), Manchot (I929), 

 Petersen (I925) and Fischel (I92I). 



OpKc Stalk- 



Course 

 optic n«i 



ittc 51alk 



'lapetum 



Fig. 

 Fig. 



Fig. 

 Fig. 



1. 



2. 



Sc)iema of the topographical relations of the eye anlagen ( ' Augenplatten' ) 

 in the early neural plate of an axolotl egg. (Copied from Woerdeman, 1929.) 

 Schema of a young urodelan neurula: the cross-hatched territory represents 

 tfie material for the optic vesicles, optic stalks, and the recessus opticus, 

 the broken line outlines the territory which the same material will occupy 

 m the stage when the neural folds have elevated. (Copied from Manchot, 

 1929.) 



Schema of the topography of the optic anlage, according to Peterson, 1923. 

 Schema of the topography of the optic anlagen, according to Fischel, 1921. 



From Adelmann 1950: Jour. Exp. Zool. 57:225. 



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