259 



interferes with identification of the species or determination 

 of sex or breeding condition. 



The statement made by me ('97, p. 20) that "this is, I be- 

 lieve, the first application of the centrifugal machine to quan- 

 titative plankton work" requires modification. In Kraemer's 

 account of Samoan plankton ('97) he describes a traveler's 

 centrifuge for use on shipboard for measurement of plankton, 

 and I infer from his text that this machine was in use by 

 him in 1893-95 in Samoan waters, though 1 find no explicit 

 statement to that effect. If this be true, his use antedates 

 ours, which did not pass the experimental stage until January, 

 1896. In any case the measurements he publishes ('97) were 

 made by the centrifuge. The following statement made by 

 Ward and Gray bill ('00), — "Juday ('97) was apparently the first 

 to publish an account of the use of the centrifuge for this pur- 

 pose. Both Dr. Kofoid and I had, however, experimented indepen- 

 dently for more than a year before that, and had written to var- 

 ious investigators regarding the advantage of such an instru- 

 ment," — requires notice in this connection, since the question has 

 been raised by these writers as to the priority in publication of 

 the use of the centrifuge for plankton measurement, and the 

 facts are incorrectly given. The date of Juday's paper is subse- 

 quent to May 28, 1897,""' for the volume containing the paper 

 contains the records of the field meeting of the Indiana Acad- 

 emy held on that date. The date of publication of my ac- 

 count of the centrifuge was March 10, 1897, and it was also 

 mentioned by Professor Forbes ('96) in the biennial report of 

 our Station operations. This report was again issued January 

 24, 1897, in separate form, and distributed to plankton investi- 

 gators generally. The date of publication of Kraemer's work 

 is "Ende Januar oder Anfang Februar 1897; genauer konnen 

 wir das Datum leider nicht augeben," according to informa- 

 tion received by me from the publishers Lipsius and Tischer, 

 of Kiel, Germany. The empty honor of first publication thus 

 probably belongs to us, and certainly not to Juday as Ward 



*In a letter Mr. Juday informs me that his paper was published in August, i897_ 



