ALG^. I I 5 



some injurious gases generated at the time, or by 

 the minute green bodies ah'cady mentioned entering 

 their gills and impeding respiration, is a question not 

 yet determined. 



Various popular explanations have been given of 

 this breaking, the more generally accepted one being 

 that it results from the seeds of aquatic plants, grow- 

 ing on the margin of the mere, falling into the water ; 

 and there is some probability on the face of this 

 explanation, because it generally occurs in the autumn, 

 when plants begin to drop their seeds, and the green 

 bodies somewhat resemble a minute seed. In 1878 

 it was intimated that the real cause was the rapid 

 germination of a minute plant classed amongst the 

 algae, and formerly known as Conferva ccJiinata, but 

 which it was suggested should be called Rivularia 

 articiilata or Rivularia ecJiinata (Fig, 22). 



It is necessary to observe that the phenomenon 

 called " breaking " must be distinguished from a 

 turbid or muddy state of the water, produced by 

 heavy rains washing down vegetable fragments and 

 earth. If we examine water under the microscope, 

 changed in its appearance by this latter cause, we 

 do not find one or two small vegetable organisms 

 pervading the whole body of the water, imparting to 

 it their own peculiar colour, as in true "breaking." 

 Nor must we confound with it an occasional and 

 partial occurrence of alga; in small quantities, for at 

 any time during the year interesting species of these 

 minute plants can be found, by diligent searching, in 

 nearly every gently running stream, quiet pool, and 

 inere. It can be most readily detected by the uniform 



