Automatism of Anuran Lymph Hearts as Obtained by Transplantation

Abstract

Although the normal lymph hearts of Anura are typically neurogenic (Briicke and Umrath 1 ) even to being homolaterally synchronized (Pratt and Reid 2 ) the beating of these organs in situ after interruption of the spinal nerve impulses has often been observed. Such preparations, even if intrinsically ganglion-free, do not altogether eliminate the possibility of some peripheral nervous influence. Moreover, the full, regular beats of excised lymph hearts in isotonic salt solutions originally observed by Moore 3 were not obtained by Brücke, 4 whose results by the same method (irregular contractions like the fibrillations of the blood heart) have since been confirmed by the writer. The method here described, permitting indefinitely continued observation with isolation in a favorable environment, has made possible the recognition and detailed study of a fully developed automatic rhythm.

An anterior lymph heart exposed by the dorsal route is cut away from the surrounding muscles, the hooked transverse process of the third vertebra, and the vertebral vein. The tongue is everted and a small incision made in the basihyoid (retrolingual) membrane near the posterior border of the underlying lymph sac (sinus basi-hyoideus). The extirpated lymph heart, a collapsed oval sac, is inserted through this opening and moved forward to the anterior margin of the sinus, where it usually becomes fixed by the connective tissue. The transparency of the membrane covering this lymph sinus makes it possible to observe the implant at any time by simply everting the tongue.

The observations were made on etherized or spinal animals, usually 10 days or more after operation. In every instance the transplanted tissue had become a firm, spherical mass. In all but 2 of the 13 active cases the tissue was well vascularized by connections with the vessels of the tongue.