. The dynamics of living matter. Biochemistry; Reproduction; Regeneration (Animals). 212 DYNAMICS OF LIVING MATTER He mentions that in the short pieces less "polarity" exists than in the long pieces; but as the conception of heteromorphosis is the opposite of polarity, Morgan's statement is only a different way of expressing the same fact. I remember that when Miss Bickford made her experiments on regeneration in Tubularians in my laboratory, I was struck with the fact that in the very small pieces cut out of a stem the polyps at the oral and the aboral end developed practically simu
. The dynamics of living matter. Biochemistry; Reproduction; Regeneration (Animals). 212 DYNAMICS OF LIVING MATTER He mentions that in the short pieces less "polarity" exists than in the long pieces; but as the conception of heteromorphosis is the opposite of polarity, Morgan's statement is only a different way of expressing the same fact. I remember that when Miss Bickford made her experiments on regeneration in Tubularians in my laboratory, I was struck with the fact that in the very small pieces cut out of a stem the polyps at the oral and the aboral end developed practically simultaneously. Here, too, polarity was less pronounced in small pieces than in large pieces. I believe the reason for this lies in the role which processes of the character of a current or a flow of material play in these phenomena. The red pigment, and possibly other substances which are of importance for regeneration, gather not in one point but in an area of the length of several millimeters, where a polyp is to be formed. If the regener- ating piece is in itself only a few millimeters long, the pigment must remain scattered equally over the small piece, and hence the polarity must disappear. Something similar may occur in the case of a Planarian. If the piece is very small, the head-forming material will remain equally distributed through the whole length of the piece, and hence the chance for the simultaneous formation of the head at either end is greater than in a large piece. It is a general experience that in order to get a duplication of organs, the regenerating animal must be split into two pieces. Thus, in order to obtain two larvae from one egg, the egg must be cut into two, or the heap of cells must be separated into two parts. One might believe that in order to get two heads in front of a Planarian, the front end would have to be separated into two by a longitudinal incision. Two heads, however, often develop in front of a Planarian whose head has been cut off withou
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