72 BULLETIN OV THE Bl'REAT' OF FISHERIES. 



tions should obtain thioiii^hout the entire experiment. To meet thr criticisni that 

 the removal of mucus from tlie surface introduced an abnormal condition intb the 

 experiment, fishes were in some cases weij^-hed after beinjr sinii)ly drained for a 

 period upon a towel. ( )f course the weight determinations in these cases were not 

 so accurate. 



Experiment li I . 



New York, X\n-\\, 1905. F. /leteroc/itu-i, from salt water of the New York 

 Aquarium (densitj- 1.008, temperature 5- C, at commencement of experiment), 

 unfed for 4 days, divided into lots of 25 each, and treated as follows: 

 (a) Kept in salt water (l.OOS to l.OlO. durinj^' period of experiment). 



Ai.ril s 249. o 



9 247. ti 



10 247.0 



11 245.8 



12 24n.O 



18 244.0 



15 24:^.5 



Loss of weij^'lit 1 per cent during first '2 days, 2.4 per ccMit during first 7 

 days. 



This lot of fish .serves as a good control for the others of the series. 

 (J) Put into running fresh water (temperature 8" C). 



Grams. 



April 9, :5 p. m - 194. 2 



9, H.06 p. in 194.9 



9, 4.05 p. m 196. 7 



10 198. 5 (all well) 



11 197.3 (all well) 



12 195. 6 (a few boginniug to .siekeu) 



lo 194. 6 (fungus appearing) 



During the next 4 days a number of fishes were removed, .some of these 

 having fallen prey to fungus. April 17, 5.30 p. ni., the remaining 14 fishes 

 weighed 109.(5 grams. They were then transferred to salt water of densit\ 

 1.018. At r).20 p. m. they weighed 108. 6 grams; April 18 (p. m.). loo.f, 

 grams. 



Results: An appreciable gain in o minutes after transfer to fresh water: a 

 gain of 1.3 per cent in 1 hour; a gain of 2.2 per cent in 1 day, followed by 

 loss, as in a above; after change to salt water, a loss of 8.2 per cent in 1 day. 



It is to be noted that the loss of weight after the second change was much 

 greater than the gain after the first. 



(h') Boiled (fresh) water used, instead of running watei-, resulting in a gain of 

 5 per cent in 1 day, 14 per cent in 2 days. 



In this experiment 4 fi.shes were sick on the second day. while all but 4 

 were dead on the third. Here and elsewhere the death of the fish was 

 accompiuiied by much more rapid imbibition of water. 



