318 Modern Fishculture in Fresh and Salt Water. 



that year of a fungus-growth disease", whereas in i8yo 

 none died, notwithstanding the mere broke badly. 



"It is said of Blake Meer, one of the meres near 

 Ellesmere, that this phenomenon does not occur, and 

 the water there is selected for drinking purposes, while 

 the other meres are in the breakage state. * * * 

 You will now be prepared to know that this breaking 

 of the meres is due to microscopic algae, of which va- 

 rious species cause the phenomenal appearance. Dr. 

 Drummond found the green color of the water of Lake 

 Glaslough in Ireland owing to vast quantities of a floc- 

 culent oscillating algae. In Loch Hainining in Selkirk- 

 shire a rich purple color occurs on the surface owing to 

 the presence, according to Dr. Greville, of an alga of 

 the genus Lyngbya. In a loch near Aberdeen a species 

 of Rivularia caused the peculiar appearance; another 

 species, Anabccna flos-aquae, was also present." 



See chapter on diseases. 



CHAPTER XLIV. 



FISHWAYS. 



A small fishway, or, as some call it, a "fish ladder" 

 is often needed by the fishculturist to enable fish to 

 surmount a dam. If possible this should be above the 

 dam, its upper end extending into the pond, or many 

 fish will pass its outlet and remain at the dam vainly 

 trying to ascend. Space forbids going into this ques- 

 tion in extenso, but as a 6-foot dam, having a fishway 



