September 25, 1914] 



SCIENCE 



455 



show conclusively that no concentration of 

 radiation on the retina from any artificial 

 illuminant is sufficient to produce injury 

 thereto under any practical conditions. 



Eclipse blindness, the only thermic effect on 

 the retina of common occurrence clinically, is 

 due to the action of the concentrated heat on 

 the pigment epithelium and chorioid, this heat 

 being almost wholly due to radiations of the 

 visible spectrum, within which the maximum 

 solar energy lies. 



The abiotic energy in the solar spectrum is 

 a meager remnant between wave-lengths 

 295 jxfi and 305 njx, aggregating hardly a 

 quarter of one per cent, of the total. At high 

 altitudes and in clear air it is sufBcient to 

 produce slight abiotic effects such as are noted 

 in snow blindness and solar erythema, the 

 former only occurring with long exposures 

 under very favorable circumstances and the 

 latter being in ordinary cases complicated by 

 an erythema due to heat alone. The amount 

 of abiotic energy required to produce a specific 

 effect in solar erythema is substantially the 

 same as that required for mild photophthalmia. 



Erythropsia is not in any way connected 

 with the exposure of the eye to ultra-violet 

 radiations, but is merely a special ease of color 

 fatigue temporary and without pathological 

 significance. 



Vernal catarrh and senile cataract we can. 

 find no evidence for considering as due to 

 radiations of any kind. 



Glass blowers' cataract, often charged to 

 specific radiation, ultra-violet or other, we 

 regard as probably due to the overheating of 

 the eye as a whole with consequent disturbed 

 nutrition of the lens. 



Commercial illuminants we find to be en- 

 tirely free of danger under the ordinary condi- 

 tions of their use. The abiotic radiations, 

 furnished by even the most powerful of theni, 

 are too small in amount to produce danger of 

 photophthalmia under ordinary working con- 

 ditions even when accidentally used without 

 their globes. The glass enclosing globes used 

 with all practical commercial illuminants are 

 amply sufficient to reduce any abiotic radia- 

 tions very far below the danger point. 



Under ordinary conditions no glasses of any 

 kind are required as protection against abiotic 

 radiations. The chief usefulness of protec- 

 tive glasses lies not so much in their absorption 

 of any specific radiations, as in their reducing 

 the total amount of light to a point where it 

 ceases to be psychologically disagreeable or to 

 be inconveniently dazzling. Glasses which cut 

 off both ends of the spectrum and transmit 

 chiefly only rays of relatively high luminosity, 

 give the maximum visibility with the minimum 

 reception of energy. For protection against 

 abiotic action in experimentation, or in the 

 snow fields, ordinary colored glasses are quite 

 sufficient. 



So far as direct destruction of bacteria 

 within the cornea or any other tissues of the 

 body is concerned, abiotic radiations possess 

 no therapeutic value. This is due to the fact 

 that abiotic radiations that are able to pene- 

 trate the tissues are more destructive to the 

 latter than to bacteria. 



E. H. Verhoeff, 

 Louis Bell 



SOCIETIES AND ACADEMIES 



THE AMERICAN MATHEMATICAL SOCIETY 



Bt invitation of Brown University, the twenty- 

 first summer meeting of the society was held at 

 that institution on Tuesday and Wednesday, Sep- 

 tember 8-9, in connection with the celebration of 

 the one hundred and fiftieth anniversary of the 

 founding of the university. Two sessions were 

 held on Tuesday and a morning session on Wednes- 

 day, the attendance including fifty-two members. 

 President Van Vleek occupied the chair at the 

 morning sessions, being relieved by Vice-president 

 L. P. Eisenhart at the Tuesday afternoon session. 

 New members were elected as follows: Mr. L. K. 

 Adkins, University of Minnesota; Dr. Lennie P. 

 Copeland, Wellesley College; Mr. J. W. Cromwell, 

 Jr., Washington, D. C, High Schools; Professor 

 Tsuruichi Hayashi, Tohoku Imperial University, 

 Sendai, Japan; Professor C. I. Palmer, Armour In- 

 stitute of Technology; Mr. Gr. A. Pfeiffer, Columbia 

 University; Mr. P. B. Eider, Yale University; Dr. 

 Alfred Rosenblatt, University of Cracow; Miss 

 Caroline E. Seely, Columbia University. Eleven 

 applications for membership were received. It was 

 decided to hold the annual meeting about January 

 1, the exact date to be so fixed that those who wish 



