TRANSPLANTATIONS 26l 



at intervals during the next two weeks. Balancers are not permanent structures. (See 

 papers by Bodenstein I9I4-3; Harrison, I92I+; Kollros, iglf-O; Nicholas, 1924; l^otmann, 1935; 

 Schotte and Edds, 19^0.) 



Make drawing or photographic records of individuals at appropriate intervals. 



OBSEBVATIONS AMD EXPERIMENTAL DATA: 



Each experiment will be peculiar to itself in that it is impossible from a technical 

 point of view, to exactly repeat any operation. For this reason it is important that the 

 student make numerous records, drawings, or photographs, to indicate (a) the donor area 

 (b) the depth of the donor tissue transplanted (c) the site on the host and the depth of 

 the excavation (d) the orientation of the donor transplant in the host field (e) and 

 periodic drawings or photographs of the success of the transplant. Only when a transplant 

 might Involve the central nervous system (e.g., the eye) should the material be sectioned 

 to determine the nenroua connections established. Space is provided with each section for 

 such records. 



DISCUSSION: 



The value of these experiments is the establishment of the stage in development when 

 various organ anlagen are determined, and the degree of determination. Detailed experi- 

 ments on the limb and eye are provided elsewhere, but it is instructive for the student to 

 determine for himself the fact that certain anlagen are exchangeable and that certain 

 transplantations are perfectly viable while others (see Twitty, 1937, Humphrey and Burns, 

 1959, and Eakln and Harris, 191+5) are not. 



There are, of course, numerous other anlagen that can be used such as the sense plate 

 (stage #1^+), the olfactory placode (stage #15), the lens (stage #l6), the ear, parts of 

 the nervous system (Detwller, 19^+2), thyroid (Allen, I9I8), pituitary (Blount, 1933), 

 gonads (Burns, I928, Humphrey, 19'+'+), and heart (Copenhaver, 19^+5). The basic procedure 

 can be established with the above four organ anlagen. (See sections on Eye, Heart, Limb.) 



Heteroplastic grafting (graft location different from the graft source) is instruc- 

 tive in relation to growth and differentiation, and may give data on rate of growth, early 

 and ultimate size factors, pigmentation, inhibitions found to exist in the normal environ- 

 ment but non-existent In the transplant environment, mutual compatibility, etc. The stu- 

 dent should consult the Glossary for the distinction between the various types of trans- 

 plants such as homoplastic, heteroplastic, heterotopic, xenoplastlc, and the extreme case 

 of the chimera (Baltzer, I9I+I) . 



EEFEEENCES 



Allen, B. M., I918 - "The results of thyroid removal in the larvae of Sana plplens." Jour. 



Exp. Zool. 2l+:l+99. 

 Atwell, W. J. & J. W. Taft, I9I+O - "Functional transplants of the epithelial hypopfiy^ts in 



three species of Amblystoma." Proc. Boo. Exp. Biol. & Med. l+l+:53. 

 Baltzer, F., I9U1 - "Untersuchungen an chlmaren von Urodelen und Hyla." Eev. sulsse de 



Zool. k^iklk. 

 Blount, B. F., 1939 - "Heteroplastic transplantation of hypophysis between different 



species of Amblystoma." Proc. Soc. Exp. Biol. & Med. 1+0:212. 

 Bodenstein, D. , I9I+3 - "An analysis of balancer development In Triturus torosus." Physiol. 



Zool. 16 :!+!+. 

 Bom, G. 1897 - "Uber Verwachsungsversuche mit Amphiblenlarven. " Arch. f. Ent. mech. 



l+:349. 

 Bums, E. K. , Jr., I928 - "The transplantation of larval gonads in Urodele amphibians." 



Anat. Eec. 39:177- 

 Copenhaver, W. M., I9I+5 - "Heteroplastic transplantation of the sinus venosus between two 



species of Amblystoma." Jour. Exp. Zool. 100:203. 

 Detwller, S. B., I938 - "Heteroplastic transplantation of somites." Jour. Exp. Zool. 



79:361. 

 Detwller, S. E., I9I+2 - "Neuroembryology." MacMlllan. 



