880 



SCIENCE 



[N. S. Vol. XXXVII. No. 949 



trical conductivity of living tissues in various 

 solutions. The results show conclusively that a 

 great variety of ions readily penetrate living cells 

 and that this penetration may be markedly hin- 

 dered or accelerated by the addition of various 

 substances to the solution. The addition of anes- 

 thetics, such as ether and chloroform, has a retard- 

 ing effect on the penetration. It would seem, 

 therefore, that these substances should retard all 

 physiological processes which depend on the trans- 

 port of ions through living tissues. 



Plants which Require Sodium: W. J. V. Osteb- 



HOUT, Harvard University. 



It is generally believed that plants do not 

 require sodium, although it is indispensable for 

 animals. Our increasing knowledge of the bio- 

 logical role of salts makes it clear that such a dis- 

 tinction between plants and animals is of funda- 

 mental importance, provided it be true in all cases. 

 But if exceptions to it be found its significance 

 largely disappears. I have therefore undertaken 

 to ascertain whether or not there are plants which 

 require sodium and have begun by examining somo 

 marine plants. The results are as follows : 



The marine plants studied require sodium; its 

 replacement in sea water by NHj, Ca, Mg, K, Ba, 

 Sr, Cs, Eb or Li is very injurious. 



The best substitutes for Na are the other salts 

 of the sea water, Mg, Ca and K. 



The diversity in behavior of various species 

 toward the salts which were used to replace the 

 sodium shows that each of these salts has a specific 

 role in life processes. 



Studies of the Wild Oat: W. M. Atwood, Univer- 

 sity of Chicago. 



Avena fatua (L.) has become a pest agricul- 

 turally in the small grain regions of the north and 

 west. In studying its germinative qualities we 

 have found it to possess high vitality. This 

 differs from the deductions which might be drawn 

 from the results of other workers who have tested 

 the seed after periods of burial in the ground. 



Avena fatua germinates poorly after harvest, 

 but the per cent, of germination increases steadily 

 up to the succeeding spring and summer. 



The early delay of germination appears to be 

 due neither to the chemical condition of the 

 embryo nor to coat obstructions to water entry. 

 Oxygen seems to be the limiting factor to germina- 

 tion which can be forced by breaking the coats or 

 increasing the oxygen pressure. 



Investigations are now under way to determine 

 whether the so-called "after-ripening" of the 



seed is due to alterations in the oxygen demands 

 of the embryo or to increased permeability of the 

 coat to oxygen. 

 Toxicity of Smohe: Lee J. Knight and William 



Crocker, University of Chicago. 



Molisch has found tobacco smoke extremely toxic 

 to plants of various kinds ranging from bacteria 

 to the highest angiosperms. He finds this toxicity 

 is not due to volatilized nicotine, for cellulose 

 paper smoke is as toxic, but believes it is due to 

 CO. 



In the burning of organic compounds the de- 

 structive distillation carbon-bearing gases, 00, 

 C2H2, C,H, and OH, are not generally completely 

 burned and may be the source of injury in the 

 smoke. Exact experiments on the delicate sweet- 

 pea seedling. Early Cromer, shows that smoke 

 from cigarettes, cigars and cellulose paper cigar- 

 ettes does not contain sufficient CO, C^H, or CH, 

 to determine 1/200 the toxicity of the smoke. 

 This leaves C;Hj, which we have already shown 

 as extremely toxic to plants, as the substance prob- 

 ably determining the toxicity. The injury from 

 smoke in our cities has been attributed to SO™ 

 and SO3, so far as gases are concerned. The 

 possible effect of the dry distillation of carbon- 

 bearing gases has been entirely neglected. They 

 are produced in small amounts in the burning of 

 coal. This coupled with their extreme toxicity 

 (especially ethylene) makes them probable factors 

 in the smoke question. 

 A Delicate Test Seedling: William Crocker, Lee 



J. Knight and E. Catlin Eose, University of 



Chicago. 



We have already published on the characteristic 

 response that the etiolate of sweet pea seedlings 

 give to ethylene. It has been termed a triple 

 response, since it is marked by reduction in rate 

 of elongation, increased growth in diameter and 

 diageotropism. We have since studied the effect 

 of more than fifty gases and vapors upon the 

 seedling, including the paint solvents, the possible 

 impurities of laboratory air, the main constituents 

 of illuminating gas and the principal distillation 

 products of coal tar. The seedlings are appar- 

 ently reliable and extremely delicate in testing for 

 ethylene — 2,000 to 5,000 times as delicate as gas 

 analysis methods. While a few other gases and 

 vapors, carbon monoxide, acetylene, benzene, tolu- 

 ene, xylene, thiophene, cumene and others give the 

 triple response they must be present in such quan- 

 tities as to be easily detected by other means or 

 they are excluded through impossibility of their 



