EDITORIAL. 



PERIDINIUM. 



For a number of years the Bureau of Health has received many com- 

 plaints from the residents of Bataan Province to the effect that the 

 dumpings from the sanitary barge Pluto caused a great mortality among 

 the fish along the shores of that province. An investigation into the 

 matter, conducted by Deputy Commissioner H. M. Smith of the United 

 States Pish Commission steamer Albatross, proved that the mortality 

 among fish is in no way connected with the Pluto but is due to visitations 

 of Peridinium in Manila Bay. The following is taken from a report on 

 this subject by Dr. Smith : 



There have been at least three visitations of Peridinium in Manila 

 Bay during the current year, a noteworthy one occurring in the. latter 

 part of January. The discoloration of the water at that time was ob- 

 served about the 23d of the month, and increased in intensity until the 

 26th or 27th, after which it rapidly diminished and practically disap- 

 peared from the head of the bay by the 31st. Another visitation was 

 observed during the third week in March but was less extensive than the 

 foregoing. 



Whenever Peridinium has invaded Manila Bay, the water over large 

 areas has been made turbid by minute protozoa, and at a distance has 

 the peculiar pale reddish color characteristic of such invasions. When 

 the water was viewed over the side of the Albatross, another color was 

 seen; and a very pronounced iron-rust tinge was observed when the 

 animals were closely packed. The rusty color was found to be due to 

 contained chlorophjd. At times, dense masses of Peridinium floated past 

 the Albatross in wavy bands several yards wide and hundreds of feet long. 



During the prevalence of these invasions, the bay is unusually phos- 

 phorescent, and tests show that the Peridinium is the chief cause of the 

 luminosity. A tumblerful of water taken at night alongside the Albatross, 

 and found to be thick with the organisms to the exchision of all other 

 creatures, glowed brightly with a blue light when carried to a dark room 

 and agitated. 



Whenever Peridinium has appeared in the bay, there has been a re- 

 markable scarcity of other forms of animal life. The dense schools of 

 small fish (Atherina and others) which are nearly always present in tlie 



surface waters of the bay, and are so eonspiciious about the wharves and 



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