REPORT OF COMMISSIONER OF FISH AND FISHERIES. 131 



LAKE ERIE. 



The systematic study of the biological features of Lake Erie was 

 resumed on Julj^ 1 and actively prosecuted for two months under the 

 direction of Prof. Jacob Reighard, of the Universit}^ of Michigan. 

 Those assisting in the work were Prof. H. B. Ward, of the Universitj^ 

 of Nebraska; Dr. H. S. Jennings, of Dartmouth College; Dr. Julia 

 Snow, of the Universit}^ of Michigan; Mr. R. H. Pond, of the Uni- 

 versity of Michigan; Mrs. H. S. Jennings, Mr. J. H. McClellan, Dr. 

 Charles Hill, and Mr. A. B. Lewis. The hatching station of the Com- 

 mission at Put-in Bay was used as a laboratorj^ as heretofore, and was 

 the headquarters of the party. Those who pursued studies at Put-in 

 Bay were Dr. Jennings, Dr. Snow, and Mr. Pond. 



Dr. Jennings resumed the studies in which he was engaged in the 

 previous year, namely, experimental investigations of the reactions 

 of the protozoa of the lake to stimuli. The principles underlying the 

 movements of these small organisms are probably applicable to the 

 higher animals, including young fishes. Three papers of Dr. Jen- 

 nings, based on this work, have appeared in the American Journal of 

 Physiology for January and April, 1900, and the American Naturalist 

 for the latter month. 



Dr. Snow continued the investigations of the previous season, iden- 

 tifying numerous species of algse and determining the life-histories 

 of several, especially those occurring in the plankton. The nature of 

 Dr. Snow's investigations are thus stated by Professor Reighard: 



In order to have any permanent knowledge of the plankton algae it is necessary 

 that they be cultivated in the same manner as bacteria in culture media of differ- 

 ent sorts. When so cultivated, it is found that algae assume different forms. The 

 different forms of the same algae also occur in nature, and have been in many cases 

 described as distinct species. We can not know what species are present in the 

 lake until the life-history of each has been worked out so that we may know the 

 various forms that it assumes. 



Mr. Pond considered the question of the nutrition of the larger 

 aquatic plants, conducting some work at the University of Michigan 

 after the close of the Lake Erie work. The nature and importance of 

 the subject studied by Mr. Pond are thus stated by the director: 



It is the purpose of this investigation to find out whether the rooted aquatic 

 plants use their roots chiefly as anchors, as has been hitherto supposed, and draw 

 their nutrition wholly from the water, or whether they are nourished like other 

 plants largely through the roots. In order to determine this point Mr. Pond 

 cultivated one of the species of plants common at Put-in Bay under two sets of 

 conditions — i. e., so that the roots were in the soil and so that the roots were 

 unable to reach the soil. Some of the plants were grown in aquaria in the labor- 

 atory, while others were grown in the lake. The results in both cases were very 

 striking, and showed that in a comparatively short time plants that were rooted 

 in the soil made a gain of about 30 per cent over those that were not thus rooted, 

 ' If this rule holds for other species of plants it is a matter of con^siderable practical 

 importance. If rooted plants draw their nourishment only from the water they 

 add nothing to the sum total of the primary food supply of the water. They take 

 certain materials from the water for their growth and return these materials to 



