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BIOLOGICAL STUDIES IN MASSACHUSETTS. 
By GrorcEe C. WHIPPLE. 
GEOGRAPHICAL DISTRIBUTION OF MICROSCOPICAL ORGANISMS. 
The geographical distribution of the various microscopical 
organisms is not only an important subject, but it is an ex- 
tremely vexatious one. A great deal of study has been given 
to it, but we are yet very far from understanding this as well as 
other laws governing this kingdom. Why it is that these organ- 
isms grow vigorously in one pond and are at the same time 
absent from a neighboring one where the conditions are appar- 
ently as favorable, or why it is that they suddenly appear in 
ponds where hitherto they have never been seen, we are unable 
tosay. Solution of these problems can only be accomplished by 
long continued observation and experiment, and by the work- 
ing out of the life history of each particular organism. The 
following statistics are of some value in connection with this 
