LtM3 F lELD OPERATIONS 2?? 



HETEROTOPIC TRANSPLANTS 



The orthotopic (homotopic) position is the normal position, the heterotopic one "being 

 a different or strange position for the anlage. It is the purpose of this experiment to 

 determine the differentiating capacity of the limb anlage at other than the normal regions. 

 If several donors are available, supernumerary limbs may be provided. Eemoving the ecto- 

 derm and/ or the mesoderm from the donor, make the following transplantations: 



a. Ectoderm alone from the area "A" of donor to region "X" of host. 



b. Ectoderm and mesoderm from area "A" to region "X" of host. 



c. Ectoderm and mesoderm from area "B" to region "X" of host. 



d. Ectoderm and mesoderm from area "A" to region "Y" of host (on hand). 



In all cases it is well to place the donor and the host side by side and to locate 

 the regions concerned in both embryos before the operation Is begun. Use MS 222 (1/3,000 

 cone.) if necessary, to quiet any muscular activity. The transplant must be made quickly 

 and the transfer may be made on the point of a needle or on a small hair loop. With a 

 ball tip gently pat the transplant into place and hold it there by means of a chipped 

 coverslip (Briicke) for at least 50 minutes. If the glass cover tends to adhere to the 

 ectoderm, try a small piece of lens paper whose ends may be fastened to the Permoplast 

 base. In the case of the transplant to region "Y" on the host it will be necessary to 

 place the host in a Permoplast depression with the head protruding. Provide an adequate 

 wound area in the host, for healing is rapid. 



EECOED OF HETEROTOPIC TEANSPLANTATIONS 



