3742 The Zoologist — November, 1873. 



The seeds of sea-weeds are ever floating in the water, and ever 

 ready to find anchorage where they meet with a stable surface. So 

 universal is this sporadical growth of aquatic vegetation, that 

 I believe it impossible for a stone to be immersed in water under 

 the influence of light, without attracting the seeds of aquatic plants, 

 and these will assuredly vegetate on its surface ; and it is also a 

 most indubitable fact — a fact that loses none of its importance 

 by frequent repetition — that this humble vegetation emits, in a 

 powerful light, a series of ascending bubbles of oxygen. 



But there is another necessity, a necessity which aquarians of 

 the first and second eras, as we have seen, not merely refused to 

 acknowledge, but took the utmost pains to condemn. I think it 

 probable that every naturalist who trusts himself on the ocean, 

 even for a dozen hours, and from the deck of a sleanier snuffs the 

 invigorating breeze as it passes over the agitated surface of the 

 water, will after a while admit that some other principle is at work 

 beside the maintenance of an exact balance between the breathings 

 of sea-weeds and the breathings of sea anemones or fishes ; and 

 will perhaps also admit that motion is such a principle. It has 

 been asserted by voyagers over and over again that the sea itself 

 becomes foul during a long calm, and that its life-supporting 

 powers seem absolutely to have departed ; fishes and pelagic crabs 

 die by myriads and float on the surface, and, together with dead 

 sea-birds and detached sea-weeds, constitute a putrid, foetid, fever- 

 generating scum, more dreadful, more fatal to man, than when 

 the great deep is in its wildest and stormiest moods. The intro- 

 duction of sea-bang, sea-lettuce, sea-endive, sea-whistle, sloke, 

 dulse or carrigeen will not remedy this. Whatever quantity of 

 these life-restoratives be cast upon the waters, they will do harm 

 rather than good ; they will float on the surface, decay, and add 

 to the seething and putrpfying mass. A more powerful agent is 

 required, and Nature kindly supplies it. A breeze springs up ; a 

 change comes o'er the spirit of the scene ; motion sets in, and all 

 is restored. We read that in a space of time incredibly short, the 

 water resumes its life-sustaining power, and every trace of impurity 

 has vanished as by a miracle. These narratives must, I think, con- 

 vincingly establish to those who read them, the fact that there is no 

 necessity for changing the water. When the life-sustaining power 

 of the sea has been exhausted. Nature herself restores it, and the 

 restoring element is motion. She has no power to change the 



