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CONCLUSION. 



I HAVE at length brought to a conclusion a work which 

 for a considerable period has occupied much of my time and 

 many of my thoughts. The feelings which have attended its 

 progress have been various : frequently, as on the discovery 

 of new species or facts, or the elucidation of some difficult 

 point, those of pleasure and satisfaction have prevailed ; occa- 

 sionally the opposite ones of doubt, and even despair, have 

 been predominant, as when I could not satisfactorily see my 

 way through difficulties ; these feelings, however, poignant as 

 they were while they lasted, were, I am happy to say, but of 

 short duration. Next day the task was usually resumed, and 

 all the doubt and perplexities vanished before renewed ex- 

 amination. 



Those who follow after me in the investigation of this 

 department of natural science, still so rich in the discoveries 

 which it yields to deserving perseverance, while they will to 

 an extent scarcely inferior participate in the feelings of satis- 

 faction and delight which I have expressed, will, it is hoped, 

 share less those of an opposite character, now that the way 

 is opened out, and that a clearer view of the subject may be 

 obtained. 



It was my intention to have made this History of the 

 British Freshwater Alga answer more closely to the title of 

 a history than in its present form it does, and that it should 

 have contained a chapter devoted to a historical consideration 

 of the subject; this, although a difficult undertaking, would 

 have been a most grateful one, for it would have afforded an 

 opportunity of mentioning in the terms of eulogy which they 



