HISTORY OF ZOOPHYTOLOGY. 427 



out from the sides, in the manner of other seeds, certain little 

 roots by means of which it remains permanently attached ; but 

 the internal part of the egg or seed is animal, and growing 

 simultaneously with its vegetable covering, it is dispersed 

 through all the ramifications and occupies their hollow interior, 

 being developed into polypes in the lateral denticles and ex- 

 treme cells. Such was the deduction he came to from obser- 

 vations made on the growth more especially of the Sertularia 

 abietina, which he had kept alive for nearly four months in a 

 vessel of sea-water. When a new part was formed, there first 

 emerged from the stem a minute tubular joint, which rose to 

 four, five, or even eight lines in height : after some days some 

 lesser buds, regularly disposed in an alternate manner, were 

 seen on the sides of this branch, which in the course of four or 

 six days grew into cells containing perfect polypes. Hence it 

 is obvious to Baster that the stem of this and similar zoophytes 

 grows in thickness and length as plants do, and that the me- 

 dullary pith is animal, which it is not wonderful should assume 

 a dendroidal form, when we see zinc and quicksilver do the 

 same by the mere force of affinity. Trembley had already 

 pronounced the cells of the fresh- water zoophytes (Plumatella) 

 to be not the work of the polypes, but rather compartments 

 in which they concealed a part of their body ; and this fact, 

 added to those already given, makes it certain that the ani- 

 malcules of the Sertulariadse are entirely passive, and have no 

 more to do with their polypidoms than the flower has with 

 the increase and growth of the herb.* 



There is some ambiguity in Easter's statement of his opi- 

 nions, for it is not very obvious whether he believed the new- 

 formed branchlets to be themselves the eggs or seeds, or whe- 

 ther they only contained the eggs ; but be this as it may, it 

 appears scarcely doubtful that he knew nothing of the true 

 ova and their curious ovaries. The phenomena observed in 

 the production of new parts are correctly stated, but nothing 

 but wilful prejudice could blind him to the fallacy of the con- 

 sequent reasoning. The analogy attempted to be drawn be- 

 tween the eggs of zoophytes and the seeds of plants has no 



* Phil. Trans, vol. lii. pp. 108118. For Easter's works, see Hall. Bib. Bot. 

 i. 4G8. 



