EFFECTS UPON FISHES OF CHANGF:S IN SALINITY OF WATER. ()8 



Ao-iiiii, in ('xpe.riiueiit 45 (p. 7-i), specimens of /''. luLnK-lhus^ tai<eii fruiii salt 

 water of density l.(t<»7+", were thorougiiiv denuded of their scales througiiout a 

 strip alioiit 1 centimeter in width and extending from the head to the dorsal tin. 

 The lish were divided into lots of 16 each and put into water of five different 

 densities. 



In the fresli-water lot 2 died witliin the iirst -' days and tl witliin the first 7 days, 

 wiien the exp(M-inient was gi\en up owing to fungus, which appeared early and thus 

 coniplicate<l the i-esult. (Compare with experiment -il, ?>, in which normal Hshes 

 were used.) All of Garrey's fresh-water lot died within less than ?)(! hours. 



TIk' next lot were placed in water having a density of about I.noi (sea water - 

 l.u^n to l.Oi'S). Only one lish (apparently one otherwise iujurt'd) dietl during ."> days, 

 after which the experiment had to he given up owing to fungus. 



The third lot, placed in the salt water of the aipiarium supply (I.n(i7), were all 

 well at the end of 5 days, when the experiment was discontinued. 



Tile fV)urth lot were {Kit into a stronger salt water brought from Sandy Hook 

 (density l.dl-t. i. i'.. about onediaU' the salinity of normal sea water). They were kept 

 in a tub without aeration. One fish died in ."■> days. 



The fifth lot were placed in water of a density 1.0-^.5 (Sandy Hook water, strength- 

 ened by the addition of a commercial sea salt, thus raising the density somewluit 

 abo\c that of the sea water at Woods Hole). Thi-ec died within the first 4 days, after 

 w liich f] (lays more elapsed without a single death. It was found that the injured sur- 

 faces had hetiled and that the scales had l)egun to regenerate. All of (iarrey's salt- 

 water lot died, though he doe.s not tell us how soon. 



The changes in weight undergone bv these scra))ed fishes aie verv insiructi\'( 

 and will be dealt with later. 



The t.'mperature of the fresh water at this time was S t() it C, that of the su!* 

 water being- 4 to (i . The fishes had not been fed for more than 1(5 days prior f. 

 the experiment. 



During the simnner of I'.tOo a few similar experiments were performed. The 

 conditions were, however, necessarily difierent. The salinity of the water from 

 which the tishes came was here more than thi'ee times that of the water at the New 

 York A(iU!irium. while the temperature was of course verv nmch highei'. 

 K.,;„r;u.„t IS. 



Woods Hole, August. I'.MC. Thirty /: //<Yc/Y>r///,/,v denuded of scales over 

 one entire side of the body. Divided into lots of 10 each \\ hicli were put into 

 salt water, fresh water, and water of density 1.001, respectix ciy. During the 

 pei'iod covered by the experiment (14 days) the results were as follows: (a) 

 In salt water, 3 dead, 7 alive and apparently well; Q)) in fresh water, all 

 dead in from :i to 13 days; (c) in l.ool water, none dead. In the last case (c) 

 the water contained 1 part of fresh to at)out 25 parts of sea water. 

 E.rp,niund I'J, 



Woods Hole, summer of llt(»5. Seven tishes in fr(>sh water all died within 

 24 hours. 



" This being the density of New Y<.rk Bay water at this time of tlie year. See ]). i;k. 



