REGENERATION 



315 



FROG TADPOLE (STAGE #25) SHOWING LEVELS 

 OF CUTS FOR TAIL-FIH REGENERATION STUDIES 



A - V-shaped cut with apex away from 



the body. 

 B - Transverse cut angled toward 



dorsal body. 

 C - Transverse cut angled toward 



belly. 

 D - V-shaped cut with apex toward the 



body. 



h. Consult the accompanying diagram of a frog tadpole (stage #25) to determine 

 the angles of the various cuts prescribed. All but "a" and "f" (the con- 

 trol) are Illustrated. 



5. Prepare an operating Syracuse dish with Permoplast base. Fill the dish with 

 one of the above (5) solutions, beginning with the 10^ Standard. Transfer 

 all (5) tadpoles successively from each of the finger bowls containing the 

 10^ Standard to the operating dish and cut the tail fin in the manner Indi- 

 cated on the previously-marked finger bowl. That is, there will be finally 

 18 finger bowls, containing six (6) different solutions, and representing 

 five (5) different cuts, and a set of controls. The cuts should be made 

 with a sharp scalpel while the tadpoles are immobilized with l/ 10, 000 MS 222 

 ( made up in the same medium) . If the cuts are made on the group from a 

 single finger bowl^ while in the same Syracuse dish, It will be somewhat 

 easier to insure the cuts being similar. 



6. Immediately return the tadpoles to the finger bowl with the appropriate 

 medium, and properly marked. It Is best to make the cut in the medium to 

 be tested. (Do not save the tail tips unless for incidental chromosome 

 counts - see -Tail Tip Technique".) 



7. Place all I8 finger bowls under Identical environmental conditions of light 

 and temperature, and minimize evaporation by keeping them covered. 



The tall fins should be examined under the dissection microscope dally for about ten 

 days, and the record consists of dally sketches beginning with a sketch Immediately after 

 cutting. Note the color of the regenerating (blastema) tissue and the angle of the re- 

 generate. 



SKETCHES OF KEGENERATIfiG TAIL FINS 



