EFFECTS t'PON FISHES OF CHANGES IN SALINITY OF WATER. »( 



It will ]>e seen by reference to experiment 86 that three times this amount of 

 fhk)rine (pel' iOit grams of body weight) was yielded by the living tishes in a single 

 hour. A nuiuber of contirmatory experiments are recorded later. 

 /{.rj,,, ■/'„>< Ufa 88 and 89. 



Fishes (F. hrf, rorJitxii) were used which had been kept in fresh water for 4 



and .1 days, respectively. The mean yield of chlorine during the first day in 



these two cases was (I.(J16 per 100 grams weight of the fish. 



This figure was surprisingly large, being somewhat over one-half the (juantity 



yielded during the first da}' by the fishes from the 1.013 water, and considerably 



greater than that yielded during the second Any by the latter. The present fisho. it 



will l)e reniembei-ed. liad already spent -i or 5 da3'S in fr^esh water. It is tn he iidtcil. 



however, that in each of tiie present experiments one or moi'e of the rislio had died 



before the chlorine test was made, and that dead fishes yield up their salts more 



readily than living ones. 



Several experiments were made with the tomcod, a fish which will, under favor- 

 able conditions, survive the abrupt transfer to fresh water, and live for considerable 

 periods in the latter medium. Great difiiculty was found, however, in maintaining 

 sufficient aeration. 



Eqx'ruii.-ut DO. 



Here 3 tomcods, weighing 116 grams, were placed, after the preliminary 

 rinsing, in 40 times their weight of fresh water. Results: 0.027 gram chlorine 

 per 100 in 6 hours, 0.049 gram chlorine per 100 in 1 day. 



The fishes were all well at the end of the first 6 houi's. At the end of a day 

 1 fish was found dead (death prolnibly quite recent). 

 KriH-nineid Ul. 



This was a control experiment similai- to experiment ST. In this case all of 



the viscera were removed, chopped up and macerated, and the body cavities. 



containing more or less blood, were rinsed out, the water so used being added 



to the rest. Even in this case the quantity of chlorine thus yielded was onh' 



0.010 gram for each 100 grams weight of the fish." 



This is seen to be only a little more than one-third the amount passing from the 



living fishes in the course of 6 hours. It can not be seriously maintained, then, that 



any large part of the salts which were found in the water had left the bodies of the 



fishes by waj^ of the alimentary canal. Tiiat it passed out through the organs of 



excretion might be argued with somewhat greater plausibility. 



In two other experiments in which this species was employed the aeration was 

 quite insuflicient and the fishes soon began to die in consequence. 

 Erperiiiieiit 9,L 



Two of the fishes had died during the first hour, and the proportion of 

 chlorine passed out during this period was 0.021 per loO grams. Here the 

 phenomena were of course pathological. 

 E.tperiment 9-J. 



Death did not occur so soon, and the figure for the first hour was verv much 



intended here, not the weight o£ the viscera from which the salts 



