The technique of fusing amphibian embryos in parabiotic or telobiotic union has been used extensively in the past 50 years for a variety of experimental and educational purposes (see citations in Burns, 1955; Hamburger, 1942, 1960; Rugh, 1948). Failures with current techniques, however, are too frequent. These are occasioned, most commonly, by improper juxtaposition of the embryos to facilitate wound healing, by separation of the embryos as a result of ciliary action, by freeing the embryos from the operating dish prior to completion of wound healing, by damage produced in freeing the conjoined embryos, or by infection. Many of these difficulties arise because the methods of constraining the embryos in paraffin-beeswax or permoplast operating dishes obstruct the operator’s view. It is a less obvious, but important, disadvantage that this method also prevents the free flow of medium just at the time when optimal conditions are necessary for maintenance and healing. This is especially true when anesthetized embryos are conjoined.

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