192 J. D. Dana on Zoophytes. 
open reunited, even if previously laid out flat, like a membrane, 
and new tentacles in a short time replaced those that were cut 
off. 'Two polyps may be made to change heads, for one may be 
grafted on the body of another. Every portion of the animal 
excepting perhaps the tentacles, which failed in the hands of 
Trembley and Baker, is thus capable of forming a perfect Hydra. 
“‘ What is still more extraordinary, polyps produced in this man- 
ner grow much larger and are far more prolific in the way of 
their natural increase, than those that were never cut. It is ve- 
ry common when a polyp is divided transversely, to see a young 
one push out from one or other of the parts, and sometimes from 
both of them, in a very few hours after the operation has been 
performed; and particularly from the tail part, two or three are 
frequently protruded in different places.and at different times, long 
before that part acquires a new head, and consequently while it 
can take in no fresh nourishment to dapply them with; and yet | 
the young ones proceeding from it, under these disadvantages, 
thrive as fast, and seem as vigorous as those produced we pee 
and uncut polyps.’’* 
16. Another fact equally strange is canetineed by these animals. 
Sir John Graham Dalyell, whose investigations in this depart- 
————_—_—$——— 
* Rake er, p pp- 92, 93.—We cite the ares an remark on this subject from 
the highly classical work of G. Johnst lish ,on n British Zoophytes, (History 
of British Zoophytes, Edinburgh, 1838 ; 
‘ When such things were first catia to a little worm the attributes 
of angelic beings were assigned,t it is not wonderful that the vulgar d disbelieved, 
albeit credulity may be their besetting sin, when ‘even naturalists, familiar with 
all the miracles of the insect world, were amazed and wist not what to do. ‘ll 
faut,’ exclaimed Reaumur, “il faut porter la foi humaine plus loin qu'il n "est per; 
mis & des hommes éclairés, pour Je croire sur le premier temoignage de celui qui. 
le raconte, et assure l’avoir vu. Peut-on se résoudre A croire qu'il y ait dans la na- 
ture des animaux qu’on multiplie en les hachant, pour ainsi dire, par morceaux rt 
But this illustrious naturalist was himself the first to promulgate, and experimen 
tally to yerify, the discoveries of Abraham Trembley, which have been fully con- 
firmed by many subsequent inquirers, and are now made so familiar to us by their 
admission into elementary works and treatises on ae theology, that we read 
of them with little surprise and without eretatenes 
Pets: 
4 Vital in ev very part, not as frail man 
