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INTRODUCTION.

possible to place a fragment of any Conferva under the micro-scope, without perceiving some of the numerous forms of lifewhich dwell amongst its filaments; and the structure of many ofwhich is so beautifully adapted to the wants of the creatures,and to the existence which they are destined to lead, as toraise in the mind of the beholder the liveliest feelings ofadmiration.

The second purpose to which the Conferva are sub-servient is one of great importance, being the purificationof the fluid in which they dwell, laden, as it frequently is,with various deleterious gases, arising from the death anddecomposition of various animal and vegetable substances;thus deriving their own origin, for the most part, in themidst of impurity, they are the agents employed in removingthis impurity, which salutary office they perform in thefollowing way. Amongst the most noxious of these gases toanimal life are carbonic acid and carburetted hydrogen; nowcarbon, the base of these, constitutes the pabulum, or food, ofplants. These two gases, then, the Conferva decompose,retaining the carbon for their own support, and setting freethe oxygen and hydrogen; thus not merely decomposing andremoving what is hurtful, but restoring to the water oxygen,the essential to all animal life whether found in air or water.Seeing, then, the important purpose which these apparentlyfrail and insignificant productions fulfil, who is there whowould venture to remove even this one small and remote linkfrom the chain of Nature’s works, and would be answerablefor the consequences of its removal? Who can tell whatbaneful influence might not arise, and spread disease and deaththrough whole districts? a calamity which, even as thingsare now ordained, is occasionally permitted to overtake us.Should any individual be sceptical as to the influence ofthese productions, and whether a respiration of the kind Ihave alluded to, and attended with the same results, reallyoccurs, let him put into a tumbler of water a little of thefirst Conferva which he may meet with in his next ramble,and, placing it in the rays of the sun, watch it for a short