594 Wisconsin Academy of Sciences, Arts, and Letters, 
A BIOCHEMICAL STUDY OF THE PLANKTON OF LAKE 
MENDOTA 
Henry A. Sghuette 
Notes from the Laboratory of the Wisconsin Geological and 
Natural History Survey. XIII. 
INTRODUCTION 
The fact that the plankton of rivers, lakes and seas forms a 
not inconsiderable portion of the food of the aquatic life therein, 
and especially of the fishes, prompted a study undertaken sev¬ 
eral years ago by the Natural History Division of the Wiscon¬ 
sin Geological and Natural History Survey to determine the 
biochemical nature of the plankton of the inland lakes of Wis¬ 
consin and with particular reference to Lake Mendota. 
The nature of a plankton catch is dependent upon meteoro¬ 
logical conditions and is subject to seasonal variations. It was 
therefore necessary in this study to make frequent catches and to 
examine each catch biologically and chemically. The immediate 
cause for the investigation here recorded is the necessity of a 
preliminary survey whose methods would be adaptable to the 
general study of the larger subject at hand. It was felt that 
by a critical examination of several catches typical of the en¬ 
tire series, we would have at hand data which would lead to 
an insight into the biochemical nature of fresh water plankton. 
Data are available concerning marine plankton.^ While in- 
^ K. Brandt, Beitrage zur Kenntnis der chemischen Zusammensetzung des 
Planktons. Wissen. Meeresunters. Abteil. Kiel. N. P. Ill, (1898), 45—90. 
R. Volk, Hamburg. Elb. Enters. VIII, (19061. 
H. Kylin, Untersuchungen ueber die Biochemie der Meeresalgen. Z. physiol. 
Chem. 94, 337-425 (1915). 
Kdnig, J., and J. Bettels, Die Kohlenhydrate der Meeresalgen und daraus 
hergestellter Erzeugnisse. Z. Nahr.-Genussm. 10, 457, (1905). 
