PLANKTONIC STUDIES. 571 



the Canary island Lanzarote. I also entirely agree with Chun in 

 regard to his general views upon the chorology of the plankton, and 

 consider his investigations upon the pelagic animal world and its rela- 

 tion to the surface fauna as the most important contribution which 

 planktology has received since the pioneer discoveries of the Challenger 

 and of the Vetfor Pisaui. 



Entirely new aspects and methods have been introduced into pelagic 

 biology in the last three years by Dr. Victor Hen sen, professor of phy- 

 siology at Kiel (9 and 22). He has for a number of years thoroughly 

 studied the conditions of life of the fauna and flora of the bay of 

 Kiel, and as a member of the commission for the scientific investigation 

 of the German Ocean (at Kiel) has endeavored to improve and extend 

 the fisheries there, and by counting the fish eggs collected to get an 

 approximate idea of the number of fish in corresponding districts (9, 

 p. 2). This investigation led him to the conclusion that it was neces- 

 sary and possible to come nearer to the fundamental food supply of 

 marine animals and to determine this quantitatively. For solving this 

 problem Hen sen invented a new mathematical method (2, p. 33). He 

 constructed a new pelagic net (p. 3), and in July, 18S4, in company 

 with three other naturalists of Kiel, undertook a nine-day excursion in 

 the North Sea and Atlantic Ocean, which was extended to the Hebrides 

 and to the Gulf Stream (57° 42' N. Lat.) (p. 30). In 1887 he publislied 

 the results of this investigation in a comprehensive work containing 

 many long numerical tables, "On the Determination of the Plankton, 

 or the Animal and Vegetable Material found in the sea" (9). He used 

 the term "plankton" in place of '^Auftrieh,'' the word hitherto com- 

 monly used, because this name is not sufficiently comprehensive and 

 suitable (9, p. 1). To be sure, the German term ''Atiftrieh'' or ''pelagi- 

 Hcher Mulder,'' introduced by Johannes Muller forty years ago, was in 

 general use and has many times been used in English, French, and 

 Italian works. But I agTee with Hensen that in this, as in other 

 scientific terms, a Greek terminus technicus, capable of easier flexion, 

 is preferable. I ado])t the term Plankton in place of ^^Auftrieh;' and 

 form from it the adjective planktonic {plauMonisch). The w }iolc science 

 which treats of this important division of biology is briefly called 



])lanktology. 



Hensen regards the mathematical determination of the 2)lanlcton us, 

 the ch ief aim of planktology from a physiological standpoint. By it he 

 hopes to solve the somewhat neglected question of the cycle of matter 

 in the sea. For the purpose of solving this, and to make a trial of his 

 new method on a larger scale, Hensen, in the summer of 1889, arranged 

 a more extensive expedition in the Atlantic, which was most liberally 

 supported by the German government and by the Berlin Acadeniy 

 of Sciences. The German Emperor furnished 70,000 marks; the Berlin 



