ade whatsoaver, and usually the curve covers about eleven intervals, in the case of where you have a bit of an you get a longthoning of the tail, fou species becoming oronnic Icad, In othar words, you get a entremoly numorous, This, of course, fits into our general idea thet in a stecam waich i5 natural, tuat has no pollution of any sort,as wa usunily think cl pollution, particularily organic pollution, Mmorg nuuacrous, ~ Sg ce {+ S {a O et font by 6 MY And tne Lirst effe Q nuncor of eny one srecis, ec you have a great nuiber of species and not any too Liarge a is to make a few species becone and then as pollution gots worse and worse, we is wnat happened to ithe curve. fae LS ct ~ fouremilo cress, @ pollutant wont into that stream, an por) You will see here that on one of theso which is in t So, by Looping these continually in the water, an@ then by changes and thon, oF course, wo are not rolying entirely on that, sumer to check the River, but wo are going in again this We do have a continuous method of diagnosing river conditions. tenvorature tests wero © Now, as to the temperature test that we have done, our ained at determining what tomperatures @ stream could stand and yet remain novmal. At onco, wa realized fron our exporimonis that in a natural envirconzent ae you must think of ontimun temmcratuves because of connlication of species and not maninum temvaranturos at which organisms can live in the laboratory, This is clearly illustrated by the fact