THE PRESIDENT S ADDRESS. 



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wealth exhausted ; there is no field of research completely worked 

 out, leaving nothing more to be learned. The life history of many 

 of our most favourite fresh water objects, although before us 

 summer after summer in their adult forms, have many points in 

 their early history and development which need working out, and this 

 could be easily accomplished by systematic and painstaking obser- 

 vation. Our late President (Professor Huxley), when dealing with 

 this subject of persistent observation, mentions that commonest of 

 every common object, the Paramecium, as affording a field for 

 this kind of study. He says, "■ Nobody certainly knows whether it 

 has any other mode of reproduction except by fission. The like is 

 true also of the Acinetee — we know something about them, but 

 nothing like a complete history." And this " complete history " is 

 wanting in so many of the lower forms of animal life, that abundance 

 of work awaits the microscopical student. There is scarcely a book 

 on Biological Science we can open without its furnishing indications 

 for further work ; shadows of doubt and uncertainty float across 

 many a page, indicating the need of more light on the life history 

 and development of some of our simplest forms of life. How many 

 a tale of wondrous beauty lies unfolded in the various embryonic 

 forms met with in a single dip from our collecting bottles ? Thus 

 you see there is no difficulty on the score of scarcity of subjects ; and 

 many other lines of investigation must occur to the mind of the 

 thoughtful student. Take the development of animal life under a 

 diversity of conditions, and here we are met by a field of the most 

 fruitful work — for instance, Carl Semper, in his recently published 

 work on " Animal Life," mentions a fact in illustration of the 

 modifications of character producible from varying the conditions 

 under which development takes place. The fresh-water Crustacean 

 Branchipus stagnalis is remarkably like the Artemia salina, never- 

 theless the differences between them have always seemed sufficiently 

 conspicuous to justify their separation into two different genera. 

 Artemia salina was kept in salt water, which was constantly being- 

 diluted by the addition of fresh water till it had become perfectly 

 fresh. The Artemia, the meanwhile breeding, at the end of several 

 generations, had so gradually and completely changed their char- 

 acters, that finally they had acquired those of the genus Branchipus. 

 These observations are certainly of the greatest interest, as evidence 

 of the important changes which modifying influences, such as those 

 mentioned by Semper, may, after a certain time, ^jroduce in the 

 JouEN. Q. M. C, No. 48. a a 



