262 



SCIENCE 



[N. S. Vol. L. No. 1289 



in 1.20 HNO3, washed in distilled water, and 

 again placed in the salt solution, it is foimd 

 that the time now required for activation is 

 not shorter but is essentially the same as be- 

 fore, i. e., 8 to 10 seconds. Evidently the brief 

 exposure to the acid has restored the partly 

 altered film to its original condition. But if 

 the process of alteration in salt solution is 

 allowed to pass the critical stage (with, e. g., 

 10 seconds exposure) before transfer to the 

 acid, the latter has no passivating action, and 

 the wire continues to react until completely 

 dissolved. This observation shows that the 

 progressive modification which the film under- 

 goes in the salt solution is of a kind which is 

 rapidly and completely reversible if the metal 

 is returned to the acid before a certain critical 

 stage is reached; but after this stage is once 

 passed the whole film breaks down when the 

 wire is replaced in acid and the iron is no 

 longer protected against solution. This be- 

 havior resembles that of living cells after 

 transfer from a balanced salt-solution like sea 

 water to a toxic solution like pure m/2 NaCl, 

 as shown (e. g.) in Osterhout's experiments 

 with Laminaria; the cells undergo a progres- 

 sively injurious modification associated with 

 an alteration in the properties of the plasma- 

 m.embranes, shown by increasing permeability; 

 this change may be reversed by transfer to the 

 original medium before, but not after, the 

 modification has reached a certain critical 

 stage. Thus the characteristic power, normally 

 possessed by the living plasma-membrane, of 

 preserving intact its continuity and semi- 

 permeability is simulated in a general manner 

 by the behavior of the surface-film of passive 

 iron in dilute nitric acid. 



The action of salt-solutions upon those sur- 

 face-films (influence of nature and concentra- 

 tion of salts, relative rates of action of differ- 

 ent salts, antagonisms) will be described more 

 fully in the second part of this article. 



Ralph S. Lillie 



Tie presidential address was given by Dr. E. W. 



Gudger on "On an extraordinary method of fist- 

 ing — the use of remora for catching fish and 



turtles. ' ' 



The following papers were presented: 



Undamped electrical oscillations: C. W. Edwaesds. 



A portable printing outfit for the ecologist: Z. P. 

 Metcalp. 



Sanitation in the south: Thokndike Saville. 



Some generic distinctions in sponges: H. V. Wil- 

 son. 



A magnetic paradox: F. N. Edgerton, Jr. 



Vegetation in the closing of ponds mith special ref- 

 erence to the Kamaplain ponds of Wexford 

 county, Michigan: Collier Cobb and H. D. 

 House. 



Preliminary studies of the reproduction rate of 

 Copepoda: Fannie E. Vann. 



Deposits of voloamAd ash: John E. Smith (by 

 title). 



Asymmetry in the formation of the nervous sys- 

 tem in the frog embryo: Blackwell Markham. 



Mecent mosquito control worh in North Carolina: 

 E. W. Leibt. 



Meptilian folklore: C. 8. Brimlet. 



New or little Tcnown diatoms from, Beaufort, North 

 Carolina: J. J. Wolfe. 



Some notes on Protozoa: 



(a) Occurrence of Tintinnus serratus Kofoid in 

 Chesapeake Bay. 



(b) Arcella excavata nov. sp.: Bert Cunningham. 

 The ovary of the Gaff-topsail catfish, Feliohthys 



felis: E. W. Gudger. 

 The seventeen-year locust in North Carolina in 



1917: Z. P. Metcalp. 

 Our rats, mice and shrews: C. S. Brimlet. 

 T}ie high frequency electric furnace: P. N. Eger- 



TON, Jr. 

 The felsites of Mount Collier: John E. Smith 



(by title). 

 The inland waterway from Boston to Beaufort: 



Collier Cobb. 

 (a) A new parasitic blue-green alga. 



(b) Comparison of Rhododendron catawhiense 



with a form occurring at Ch-apel Sill: W. C. 



Cooker. 

 Locating invisible objects: C. C. Hatlet. 



Bert Cunningham, 



Secretary 



SCIENCE 



SOCIETIES AND ACADEMIES 



THE NORTH CAROLINA ACADEMY OF SCIENCE 

 The annual meeting of the North Carolina Acad- 

 emy of Science was held at Trinity College, Dur- 

 ham, on May 2 and 3. 



A Weekly Journal devoted to the Advancement at 

 Science, publishing the official notices and pro- 

 ceedings of the American Association for 

 the Advancement of Science 



Published every Friday by 



THE SOEMZE PRESS 



LANCASTER, PA. GARRISON. N. Y. 



NEW YC«K, N. Y. 



Entered in tbe poit-^c« at LaocuUt, Pa., u Moond cUm OMasr 



