54 



THE OOEAN. 



however, is now known to be incorrect : the existence 

 of ciliary action, controllable at varying intervals 

 has been proved by Dr. Dobie, and more abundantly 

 by Mr. Bowerbank ; while susceptibility to outward 

 assaults, and sudden contractility, have been proved by 

 myself to exist in some species. The substance may 

 be destroyed, but there is no contraction, nor the 

 slightest evidence of feeling ; to all appearance they 

 are as passive as the rock on which they grow. One 

 proof of their animality, however, is open to any 

 one : we are all familiar with a peculiar smell pro- 

 duced when horn, wool, feathers, &c. are burned ; 

 this smell arises from the presence of ammonia, and is 

 peculiar to animal matter : on burning a bit of 

 Sponge this animal odour is strongly perceptible. 

 On viewing a living Sponge, however, in water, witli 

 care and attention, it is found to exhibit a constant 

 and energetic action, which sufficiently shows its 

 vitality. Dr. Grant's account of his discovery of this 

 motion in a native species is so interesting, that, 

 though often quoted, I may be forgiven for repeating 

 it here. " I put a small branch of the Spongia 

 coalita, with some sea-water, into a watch-glass, 

 under the microscope : and on reflecting the light of a 

 candle through the fluid, I soon perceived that there 

 was some intestine motion in the opaque particles 

 floating through the water. On moving the watch- 

 glass, so as to bring one of the apertures on the side 

 of the Sponge fully into view, I beheld, for the first 

 time, the splendid spectacle of this living fountain 

 vomiting forth from a circular cavity an impetuous 

 torrent of liquid matter, and hurling along in rapid 



