Some AUjd' of Minti('S(>f(( — Arthitr. UU 



The thorough and able manner in which this test was made 

 leaves no reasonable doubt of the perfect harmlessness of the alguE^ 

 in a (/rowing condition.. I append this last clause, because the 

 citizens of the place still believe that the algie are at the root of the 

 trouble, and that the tests did not show it because they were nut 

 made at the right stage of their occurrence. Although no sufficient 

 study of the habits of this plant has yet been made to enable one 

 to speak with certainty, yet it does not appear from present data 

 that in some other stage it would give different results, unless it 

 be when decaying, when it turns brown or reddish brown and gives 

 off a peculiar stench. At this time the microsco])e shows the cells 

 of the algit' to be swarming with bacteria. Whether these are other 

 than the common and harmless bacteria of putrefaction is at pre- 

 sent impossible to say. The probabilities are, however, entirel}' 

 against the hypothesis that the decaying algie or the accompanying 

 Itacteria have anything to do with the trouble. 



We are therefore obliged to sum up the economic part of this 

 investigation by stating that the death of the animals is probably 

 not due to the suspected alga\ and that no clue to the real cause 

 has yet been obtained. 



The botanical part of the investigation has yielded more in- 

 t4?resting results, although far from being complete. The descrip- 

 tion of the structure of the alga, given in my first report, is suf- 

 ficient for present purposes, if there be added to the account the 

 fact that when the cylindrical spores are formed, not mentioned 

 in my report, they occupy the base of the filaments, the single 

 round cells at the end toward the centre of the mass being called 

 heterocysts; or, to use a former illustration, if the filament be re- 

 f)resented by a whip, the portion that the hand wovdd grasp is 

 where the spore forms, while the knob on the end is the heterocyst. 



One of the methods by which such algse multiply, besides the 

 usual one by spores, is by the breaking of a filament into several 

 })arts, which then arrange themselves side by side, and grow into 

 as many complete filaments. These fragmentary reproductive 

 Hlaments are known ms hormogonia. 



At the time the alga is most al)undant and consiiicuous the 

 spores are usually quite immaiure: and. ns this is the period jit 

 vihich specimens have usually beeji gathered, the comparative 

 study of the forms from different localities is rendered M^ry diffi- 

 cult and unsatisfactory. 1 can no', do b^ttfu' in this connection 



