. The dynamics of living matter . DYNAMICS OF REGENERATIVE PROCESSES 203 number of Tubularian stems; one half of these pieces were put ver- tically, but reversed, with the oral end a in the sand, in order to suppress the formation of polyps at this end. The other half of the pieces were also put vertically and reversed into the same aquarium, but in such a way that both cut ends a and b were surrounded by sea water. These latter pieces formed polyps at the oral end a after three or four days, while it took nine days for them to form polyps at the other end. The stems, however, whose oral
. The dynamics of living matter . DYNAMICS OF REGENERATIVE PROCESSES 203 number of Tubularian stems; one half of these pieces were put ver- tically, but reversed, with the oral end a in the sand, in order to suppress the formation of polyps at this end. The other half of the pieces were also put vertically and reversed into the same aquarium, but in such a way that both cut ends a and b were surrounded by sea water. These latter pieces formed polyps at the oral end a after three or four days, while it took nine days for them to form polyps at the other end. The stems, however, whose oral ends were put into the sand, where consequently the formation of polyps at the oral end was suppressed, formed polyps at the aboral end within three or four days. Hence, the suppres- sion of the forma- tion of the polyp at the oral end FlG 4I accelerated con- siderably* the formation of the polyp at the aboral end. The next question was, How can the suppression of the polyp at the oral end accelerate the formation of the polyp at the aboral end? The following experiments were intended to answer this question. r Pieces ab (see Fig. 42) were cut from a number of stems, and each of these pieces was cut in two between c and d. If ~a all four cut ends were surrounded by sea water, polyps were first formed at the oral end of each half; namely, at a and d, where the polyp formation occurred simultaneously. Con- -cd siderably later the polyps were formed at the aboral ends c and b, and here also the polyp formation occurred simul- taneously. It therefore appears as if the polarity in this b case were due to a condition of the nature of a current ( of liquid), by which certain substances were carried through the stem in the direction from the aboral to the oral end. FlG 2 The deposition of certain substances by the current at the anterior end retards the formation of the polyp at the opposite end. The idea that a current is the decisive variable in this case could be tested in anoth
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