128 Wisconsin Academy of Sciences, Arts, and Letters. 
A most recent discussion of Wasserbliithe and of the green, 
yellow or red colors given to bodies of water by various organ¬ 
isms has been written by Zaeharias (03). 
Pine Lake is similar in one respect to Jamaica Pond, viz., in 
that neither has any outlet to speak of. But, on the other hand, 
Pine Lake is considerably larger than Jamaica Pond. The 
former has an area of 1.2 sq. mi. and is about 2 miles long by 1 
mile wide; whereas the latter has an area of only 65V 2 acres. 
The smaller lake is between 50-60 feet in its deepest part; 
while the greatest depth of Pine Lake is about 90 feet. 
The growth of Oscillaioria prolifica in Pine Lake during the 
summer and fall of 1904 must have surpassed in luxuriance even 
the richest development of the plant in Jamaica Pond. For, 
inquiries show that the ice around the shores of the whole lake 
contained quantities of the alga, as evidenced by the fact that 
ice harvested on all sides contained the red color imparted by 
it. Mr. Hansen, as did the great majority of the residents 
about the shores of the lake, threw away all of his colored ice 
and replenished his supply from the neighboring Beaver Lake, 
which did not show any of the reddish growth. Two of the 
residents, however, retained some of their cut from Pine Lake, 
and I have examined specimens from the ice-houses on the 
estate of Messrs. Mayer, situated almost opposite and about one 
mile from the estate of Mr. Hansen. I was told that this ice 
was cut in January, 1905. In the most of the ice-cakes exam¬ 
ined, the reddish color, resembling the juice of crushed cherries, 
appeared in small amount only, diffused about air-bubbles and 
cracks in the ice. One of these colored areas was melted, and, 
on microscopical examination, the water thus obtained was 
found to contain the faintly reddish filaments of Oscillatoria 
prolifica. These filaments appear rather rigid and refractive, 
probably partly owing to the iarge amount of silica which, in 
the investigations quoted above, was found to be present. The 
diameter of a filament from the Pine Lake material measures 
about 4/*-5y; while the component cells are likewise about 4/x- 
5 n long. 
I was told that some of the ice at Mr. Mayer's place was col¬ 
ored throughout with the ‘‘crushed cherry" color; whereas 
