630 



SCIENCE. 



[N. S. Vol. XIX. No. 485. 



body and 82 or 83 for the caudal portion. 

 The total number is, therefore, approximately- 

 equal to the total number found in the pre- 

 vious larvffi. 



The coloration differs from that of the 

 smaller larvse in that additional spots have 

 developed along the alimentary canal and 

 along the sides. There are ten spots along 

 the alimentary canal from the gill-openings 

 to the anus. Most of these are duplicated 



described. The breeding season of this eel 

 would, therefore, extend from about the mid- 

 dle of June to the end of July. 



C. H. ElGENMANN. 



Indiana University. 



ion action. 

 It has long been the view of the writers that 

 the term ion action in the sense that it has 

 been used in pharmacology and physiology, is 



above and below, the upper one being the 

 larger. There are seven or eight spots 

 along the tail, not counting the color at 

 the tip, which is apparently much as in the 

 younger larvse. There is a marked spot 

 near the tip of the lower jaw and another 

 on the upper jaw. There are in addition to 

 these spots, which had representatives in the 

 younger larvse, a number along the sides over 

 the notochord. In the anterior part of the 

 body, the abdominal portion, these spots con- 

 sist largely of a single chromatophore between 

 two protovertebraa. Their arrangement on one 

 side is as follows : No. 1 between the seven- 

 teenth and eighteenth protovertebrse ; No. 2 

 between 28 and 29 ; No. 3 between 35 and 36 ; 

 No. 4 between 39 and 40; No. 5 between 45 

 and 46; No. 6 between 51 and 52; No. 7 be- 

 tween 55 and 56; No. 8 between 61 and 62; 

 No. 9 between 70 and 71. Those of the other 

 side have a slightly different arrangement. 



The spots on the tail have migrated up 

 from the lower margin of the body so that 

 they form a continuous series with those of 

 the middle of the sides instead of with those 

 of the alimentary canal. The last one of 

 the caudal spots is, however, still located at 

 the lower margin. Below it on the margin 

 of the fin fold is a small spot, and there is a 

 black stripe along the upper margin of the 

 body at the base of the dorsal membrane, from 

 a little in front of the last caudal spot to the 

 end of the tail. 



The size of this specimen indicates that it 

 is about a month older than those previously 



not justifiable and throws no light on the 

 nature of salt action. It seems to have been 

 accepted by many physiologists that the dif- 

 ferences observed in the action of a series of 

 analogous salts possessing, for instance, a 

 common anion are to be attributed to a specific 

 action of the cations upon the tissue. Such 

 a conclusion seems to be unwarranted. Re- 

 cent work on the catalytic decomposition of 

 hydrogen peroxide offers a good example to 

 illustrate our views. In a recent number of 

 the American Journal of Physiology there ap- 

 peared an article by Neilson and Brown* en- 

 titled ' The Effect of Ions on the Decomposi- 

 tion of Hydrogen Peroxide by Platinum 

 Black.' After a study of the effect of a series 

 of sodium salts and also a series of chlorides 

 on the rate of the catalytic decomposition 

 these authors conclude: 'In the catalytic de- 

 composition of hydrogen peroxide by platinum 

 black the cation, in general, has an inhibiting 

 or depressing effect, and the anion has an ac- 

 celerating effect.' We have recently shownf 

 that the inhibitory action of certain salts on 

 the catalytic decomposition of hydrogen per- 

 oxide by various metals is due to the forma- 

 tion of a thin insoluble film over the surface 

 of the metal by the action of the salt on the 

 metal. Thus it was shown that the catalysis 

 by a given metal is inhibited by those salts 

 whose constituent acid yields an insoluble salt 

 with the catalyzer. Thus the catalysis by 

 silver is inhibited by soluble chlorides, brom- 



* Amer. Jour, of Physiol., Vol. X., p. 225, 1904. 



fAmer. Chem. Jour., Vol. XXIX., p. 397, 1903. 



