189;i.] MICROSCOPICAL JOURNAL. 61 



5. Light for Photographing. — I wish to photograph a 

 honcv-hcc- lliat is mounted oil a lA-in. slide. With 3-incii B. ^: L. 

 stiulfiit's ol)JL-cti\c' I get too huge niagiiiticatioii and too small a 

 circle of light. It is ahoiit j, inches only, and I want to use a 

 5 plate. I caimot get a 4-inch objective to give any more light. 

 —Student. 



6. Hardening Balsam and Damar. 1 have trouble with 

 balsam and ben/ole, also \\ ith damar in l)en/.()le, on account of 

 its hardening slowlv. Sc\eral lots tVom dillerent makes give 

 same results. Can mild heat be used, or is there some better 

 medium for cpiicU work, reliable and easy of manipulation.^ 

 — Amateur. 



7. Nervous System of Sponges. — Refeiiing to the note on 

 page 48 regarding the nervous system ot the fresli-water sponges, 

 recpiest is made tor the titles of any or all papers that have been 

 published on the subject. — The I^ditor, in behalf of J. M. S. 



S. Farrant's Medium. — Why do dealers charge 50 cents for 

 an ounce of Farrant's medium, or why does any one buy it of 

 them, when anybody can make it for himself at less than 3 cents 

 per ounce .' 



Picked lumps gum acacia, . . 4 drams, 



(ihcerin, ..... 2 fluid drams. 



Camphor water. . . . . 4 '* " 



Mi.\. let it tlissolve. and strain. — F. 



LETTERS TO THE EDITOR. 



Note. — T/z/s column /.■^ open to all correspoudeuts v.'/to write npoti the 

 topics enumerated under " Problems,^'' or ivho give other information of 

 interest. The fact that a problem has been ansTXieri d once need not deter our 

 friends from making additional comments. To facilitate reference, corre- 

 spondents should cite the number as -veil as the page on zvhich have ap- 

 peared letters and </ueries to 7i'hich reference is made. The editor is not 

 responsible Jar the z'iezcs oj others published in this periodical. 



(5) Societies. — We are endeavoring to compile as correct a list 

 as possible of existing microscopical societies in the L^. S. I 

 have written to all that I have ever heard of, but suspect that there 

 are manv otheis. As your journal goes everywhere, will you not 

 request that the secretaries of all such societies communicate with 

 me, giving name and location of society, date of organization and 

 incorporation, names and addresses of officers, number of mem- 

 bers, time of meeting, publications, library, cabinet, etc. .'' — George 

 Otis Mitchell, 1034 Pine street, San Francisco, Cal. 



(6) Methods of Instruction. — You and your readers may be 

 glad to leain that an experiment in medical education with the 



