December 29, 1911] 



SCIENCE 



929 



of cases Fundulus Jieteroclitus died, either in 

 distilled water or in ordinary fresh water, 

 drawn from the water supply of New York or 

 of Woods Hole. In my own experiments with 

 healthy adult fishes, placed in ordinary " tap " 

 water, death commonly occurred after an in- 

 terval of from one day to two weeks, although 

 individuals frequently lived for a consider- 

 ably longer period, sometimes as long as they 

 were kept under observation. In some of the 

 experiments the earliest deaths occurred too 

 soon to make it possible to attribute them to 

 bacterial or fungous disease, while in the 

 great majority of fishes there was no visible 

 evidence of such disease to the last. 



I have been very careful to avoid making 

 the claim that Fundulus of this species could 

 not, under any circumstances, live for an in- 

 definite period, either in fresh or distilled 

 water. Indeed, as regards the former, I cited 

 trustworthy reports of cases in which this 

 fish had become landlocked ' in ponds, etc., 

 probably through a slow process of acclimati- 

 zation. I have, however, laid emphasis upon 

 the fact that adult specimens do commonly 

 die within a few days after transfer to 

 water entirely devoid of their accustomed 

 salts. From recent conversations with Pro- 

 fessor Loeb, I am led to understand that this 

 has likewise been his own experience.^ In- 

 deed, in a paper" published during the present 

 year he distinctly afiirms that only five per 

 cent, of his grown individuals show sufficient 

 powers of resistance (" diese grosse Wider- 

 standsf ahigheit ") to live for five weeks in 

 distilled water. On this point, then, the dif- 

 ference between us seems to be merely a mat- 

 ter of emphasis. Loeb, for his purposes, has 

 laid stress upon those cases in which the 

 fishes have survived; I have laid stress upon 

 the fact that, except for brief periods, they 

 commonly do not survive. 



In itself, it would seem to be a matter of 

 small scientific importance whether or not 



* If I am mistaken in this, I trust that Professor 

 Loeb will set me right. 



' Archiv fur EiitwioTclungsmechanilc, Bd. 31, 

 1911, pp. 654^657. 



any given species of fish can be transferred 

 with impunity from one medium to another. 

 We all know that some fishes can, while many 

 can not, endure such a transfer. But since 

 the experiments, both of Loeb and myself, in 

 this field, have dealt very largely with the 

 question whether or not this particular species 

 would survive various experimental conditions 

 which have been employed by us, it is of con- 

 siderable importance to recognize its ordinary 

 behavior in fresh water. 



In a recent article" already referred to, Loeb 

 has made much of the fact that I admittedly 

 used commercial distilled water in my ex- 

 periments, and would clearly have his readers 

 believe that the death of the fishes in these 

 experiments was due to impurities in the 

 water. It seems hardly necessary for me to 

 state that my use of water of this sort was 

 deliberate and was done with a full knowledge 

 of the fact that ordinary distilled water has 

 been found harmful to some organisms. I 

 used this sort of water for the simple reason 

 that I was not, at the time, in a position to 

 obtain sufiicient quantities of chemically pure 

 distilled water. I believe, however, that the 

 validity of my results was not aifected by the 

 character of the distilled water employed, and 

 this I hold for several reasons: (1) These fishes 

 likewise died in ordinary " tap " water, in 

 which true fresh water species lived perfectly 

 well. Loeb's suggestion that disease germs 

 may have caused the deaths in such cases is 

 negatived by the fact that death oftentimes 

 occurred within less than a day. (2) The 

 baneful effects both of the distilled water and 

 of the tap-water were abolished by the intro- 

 duction of a very small percentage either of 

 sea-water or of pure NaCl, as will be pointed 

 out below.' (3) I must repeat Loeb's own ad- 



'Archiv fur EntwicMungsmechanik (loe. cit.). 



' Here an appeal may be made to the antago- 

 nistic effect (discussed below) of the salts of sea- 

 water upon various poisons, it being assumed that 

 the distilled water had been contaminated by some 

 metallic poison. Such an assumption could not be 

 made, however, in the case of the tap water used, 

 while the action of the NaCl in the two cases 

 seems to have been identical. 



