bo 
59 
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- 
heve, 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 [infer from his text that this machine was in use by 
him in 1893-95 in Samoan waters, though I 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 Graybill (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 aninstru- 
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 kénnen 
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, 1897, 
