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THE METHODS and RESULTS of the GERMAN 



PLANKTON INVESTIGATIONS, with SPECIAL 



REFERENCE to the HENSEN NETS. 



By J. T. Jenkins, D.Sc. 



[Read May 10th, 1901.] 



Introduction. 



At the suggestion of Professor Herdman I have under- 

 taken to draw up a brief but I trust sufficient account of 

 the methods employed by the German investigators for 

 the estimation of the Plankton, that is, the floating, as 

 distinguished from the swimming, organisms which occur 

 at all times but in varying abundance in all parts of the 

 seas and oceans. I do this the more readily as I have had 

 ample opportunities of practically making myself 

 acquainted, during the past twelve months, with the 

 methods of plankton investigation as at present carried 

 out in Kiel, and as no account of these methods yet exists 

 in English. 



A short account of the results, which are of great and 

 far-reaching importance, already obtained by the German 

 workers, has also been appended ; but this latter part is 

 somewhat brief, and serves more as an indication of 

 the direction in which results have been already obtained 

 than as a summary of the results themselves. Sufficient 

 references are, however, given to the literature to enable 

 any one who might care to devote further study to the 

 question to find a full and adequate account of the con- 

 clusions already obtained. The plankton estimation 

 methods of the Germans, the credit for initiation of which 



