Olive—Occurrence of Oscillatoria Prolifica. ±27 
aigae. The phenomenon has received various names: in Eng¬ 
land it is called “breaking”; in this locality, it is sometimes 
called the “working” of the lakes. “Wasserbluthe,” “Flos 
aquae,” “waterbloom,” are also variously applied to the scum. 
In this country, Far low (77; 83, I; 83, II) has done more 
work on the subject than any other investigator. According to 
Trelease (89), Dr. Fallow .first observed the purplish color in 
Jamaica Pond, in Massachusetts, in the spring of 1884, and he 
gave to the alga the name Oscillatoria diffusa. This species was 
subsequently found, however, to correspond to the earlier de¬ 
scribed 0. prolifica (Grevilie). In his earlier paper (77), Far- 
Low discusses the odors caused by the deeay r of various organ¬ 
isms sometimes found in water supplies and speaks of Oscilla¬ 
toria and Lyngbya as causing “indescribably suffocating” 
odors; of Beggiatoa, sulphurous odors; and of the Nostocs, 
Plectonema, etc., “pig-pen” odors. In this same paper, he 
ascribes the death of the algae forming the water-bloom as due 
to the broiling hot rays of the sun. 
Magnus (83) investigated an instance in which the ice cut 
from a pond near Berlin contained a greenish growth, and, on 
examination, he found it to contain a species of Aphanizomenon. 
Trelease (89) studied the “Working” of the lakes at Madison 
and gives, in connection with his paper, a long list of articles 
relating to water-bloom. Chodat (96) has recently published 
observations on Oscdlatoria rubescens D. C., which, together 
with 0. prolifica (see Goraont, 93, p. 225), gives a reddish color 
to the surface of Lake Moral, in Switzerland. This author ap¬ 
pears to agree with Klebahn (95), in that vacuoles of gas are 
regarded as present in the cortical region of the cells of the 
Oscillatoria; and he further believes that it is this gas which 
causes the alga to rise to the surface and float. 
Moore (01) also agrees with Klebahn’s views concerning the 
presence of gas-vacuoles in water-bloom, since, after his study 
of Oscillatoria prolifica from J ainaica Pond, he came to the con¬ 
clusion that the buoyancy of the algal masses was due to the 
presence of the vacuoles, which he thought contained nitrogen. 
He was also lead to believe that the red color of the plant was 
caused by the refraction due to the presence of large numbers 
of these gas-vacuoles, as had been suggested by Klebahn. 
