42 JOURNAL OF THE [February, 



mounting, however, has to be finished at once, otherwise the 

 balsam is likely to crystallize under the edge of the cover-glass. 

 This medium is best prepared for use by dissolving it in chloro- 

 form, and carefully filtering the solution. The method of mount- 

 ing with it is similar to that with ordinary balsam. When the 

 work is done, the chloroform is expelled by one or two days' ex- 

 posure to gentle heat." 



The President said that his own observation accorded with 

 the statement of Mr. Day regarding the tendency to crystalliza- 

 tion ; that he had himself seen slides of diatoms which, though 

 prepared by an experienced hand, had become impaired through 

 the crystallization of the mounting medium. 



MULTIPLE IMAGES. 



Mr. J. D. Hyatt gave his observations on the formation of 

 multiple images by compound eyes. They are printed in full on 

 pages 33-37. 



A NEW ELECTRIC LAMP. 



The incandescence lamp which was among the objects exhib- 

 ited, was described, and its quality and working illustrated, by 

 R. W. St. Clair, M. D. " The battery," said he, " has six cells, 

 for one filling of which about five ounces of fluid are required. 

 The arc in the lamp is a vein of the beech leaf, carbonized. Its 

 life is long. I have one which has been in use more than a year. 

 The light is readily governed by making connection with more 

 or fewer of the cells. It has been tested in photomicrography 

 with satisfactory results." 



The President remarked that the electric light exhibited by 

 Dr. St. Clair is the best for brilliancy that has yet been brought 

 before the Society. 



Mr. E. A. Schultze stated that Dr. Van Heurck is employing 

 electrical illumination in photographing diatoms, and that his 

 work, which can but be of great interest and value, will soon be 

 given to the world. 



MICRO-ORGANISMS OF PNEUMO-ENTERITIS. 



Mr. R. Hitchcock, of Washington, was present, and the Presi- 

 dent invited him to favor the Society with any observations 

 which he was pleased to make. He responded ; " I brought with 



