V. OBSERVATIONS UPON SOME ALG.E WHICH 

 CAUSE "WATER BLOOM." 



N. P. B. Nelson. 



An endeavor has been made to collect some of the more im- 

 portant known facts concerning " water bloom" as it occurs in 

 Minnesota and neighboring states. It seems quite certain that 

 at least some of the algae causing this appearance in water 

 supplies are of considerable sanitary importance. It is the 

 object of this paper to give, not a complete and scientific 

 treatise, but a general and practical description of the phenome- 

 non and its causes and effects so far as known. Up to this 

 time there is no record of its occurrence to any great extent in 

 the rivers or lakes supplying drinking water to the inhabitants 

 of cities and towns of the state, but in several instances it has 

 apparently caused the death of cattle and other animals. 



Occasionally persons interested in the matter have sent speci- 

 mens to the Department of Botany at the university, and it 

 would be well if this were more generally done. Such collec- 

 tions with notes accompanying them are of the greatest aid in 

 acquiring a more general and complete knowledge of this kind 

 of vegetation. A small amount of the material, immediatelv 

 upon being taken out of the water, should be placed in a vial 

 containing a 5-per-cent. solution of formaline. It can then be 

 packed in a small box with cotton and sent at any convenient 

 time. Such a solution of formaline can be purchased for a few 

 cents at any drug store. 



History. — The first published record of the occurrence of 

 this " water bloom " in the state of Minnesota was that of J. C. 

 Arthur (1) in 1883. "A very fatal disease among cattle and 

 hogs in Waterville, Le Sueur county," was reported on the 

 8th of July, 1882. Professor Arthur visited the locality and 

 describes the condition as follows: " On June 28, 1882, after 

 two or three days of pleasant weather, the wind gathered a 

 thick scum of alga? in the little bay (on the north shore of Lake 



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