Prince, — Inimical Animals and Conditions 59 



soot persisted in clinging to the floating eggs, and Mr. 

 J. T. Cunningham and others published results which 

 they made later than my hatching experiments and thus 

 had priority. 



Chemical and physical changes in the surrounding 

 water affect fish eggs harmfully. Many of you have 

 read Dr. Knut Dahl's interesting paper on the problem 

 of sea fish hatching (Conseil Intern, pour I'Exploration 

 de la Mer. Rapports et Proc. Verb. Volume X, April, 

 1909). Hansen had found long ago vast numbers of 

 dead pelagic eggs on the bottom of the sea and Dahl no 

 doubt found the reason for this, at any rate in the condi- 

 tion in certain Norwegian fjords where he says deep lay- 

 ers of water remain unchanged and stagnant, saturated 

 with sulphuretted hydrogen and devoid of oxygen and 

 showing the absence of higher animal forms. 



FLOATING EGGS SINK AND MAY DIE. 



The varying specific gravity of the water also affects 

 pelagic eggs in a remarkable degree, and in March, 1905, 

 Dahl says that at 2 meters (78 inches or over 2 yards 

 depth) he got 12 eggs at one Station, 26 eggs at 5 meters, 

 610 eggs at 10 meters, and 1190 eggs at 30 meters; 

 possibly owing to fresh water at the surface, the cod 

 fry at the same depths were respectively 1, 4, 62 and 76. 

 In the southern waters of the Norwegian coast cod eggs 

 and larva will float in still water of an absolute specific 

 gravity of 1,021, but if below that they sink down lower 

 and lower. 



Again, winds, currents and tides affect the floating 

 eggs so that vast numbers not only drift far from their 

 original localities, but may even be washed ashore and 

 destroyed. It is on record that flat beaches have been 

 noticed glistening with untold millions of these minute 

 glassy globes, the eggs of cod, haddock, etc., just as Pro- 

 fessor Mcintosh found in Scotland a long beach strewn 

 with the delicate needle-like Sagitta after particular 

 storms and winds. 



