86 



The Mechanistic Conception of Life 



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Fig. 23. — Diagram 

 of normal regenera- 

 tion if a piece a 6 of 

 Antennularia is liung 

 up vertically in the 

 water. The piece 

 forms roots W at the 

 lower end b and a new 

 stem »S at the upper 

 end a. The old nor- 

 mal arrangement of 

 organs is thus restor- 

 ed through the pro- 

 cess of regeneration. 



Fig. 24. — Diagram 

 of heteromorphic re- 

 generation in Anten- 

 nularia. A piece a b 

 cut out of the stem 

 is hung up in an in- 

 verted position, i.e., 

 the root end b up- 

 ward and the stem 

 end a downward. In 

 this case the apical 

 end a forms roots W, 

 and the basal end b 

 forms a new stem S 

 which grows upward. 



organs in the natural development. The 

 hydroid, Antennularia antennina, above 

 mentioned, seemed to afford a suitable sub- 

 ject for experimentation in an attempt to 

 solve this problem and the following simple 

 experiments were performed. 



A piece ab (Fig. 23) of an Antennu- 

 laria was cut out and hung up vertically in 

 the water of the aquarium, the apical end 

 a above and the root end b below. It was found that after a 

 few days the root end b had formed little roots, W, which 



t/ 



Fig. 22. — A piece 

 of the normal stem 

 of Antennularia an- 

 tennina, & hydroid of 

 the Bay of Naples. 

 Approximately natu- 

 ral size. S S, stem. 

 W, stolons or roots. 



