RECORDS 97 



period of sun spots as well as through the maximum. Promi- 

 nences can be photographed nearly as well with it as at times 

 of total solar eclipse. 



Mr. Levison in his note, suggests that there is some emana- 

 tion, probably Becquerel rays, from the pasteboard of the boxes 

 in which the plates are packed for the market, which causes 

 their deterioration. He found that if he cut a star from the 

 pasteboard of a plate box and laid it on the sensitive side ol a 

 plate, the whole then being enclosed in a box for a week, when 

 he developed the plate he found an image of the star. This 

 would explain the deterioration at the edges of plates where 

 they come nearly in contact with the box, or the deterioration 

 due to the pasteboard separators at the edges of the plates. 

 The author's experiments led him to the suggestion that metal 

 boxes would be better for the plates than the pasteboard boxes. 

 Wrapping with paraffine paper might also hav^e the same effect. 



\Vm. S. Day, 



Secretary. 



SECTION OF BIOLOGY. 



February i i, 1901. 



Section met at 8:15 P. M., Professor C. L. Bristol presiding. 



The minutes of the last meeting of Section were read and 

 approved. 



The following program was then offered : 



D. T. MacDougal, The Critical Points in the Relation of 

 Light to Plants. 



A. G. Mayer, The Variations of a Newly-Arisen Species 

 of Medusa. 



Summary of Papers. 



Dr. MacDougal stated that an examination of all the data at 

 hand shows no correspondence among the maxima, minima, 

 and optima of intensities of light with regard to the various in- 

 fluences exerted upon the plant by light, and that the current 

 conception of pJiototonus is not based upon well-defined gener- 

 alizations. 



Etiolative phenomena of plants are irritable reactions, con- 



