40 



THE AMEEIOAN MONTHLY 



[February. 



stannous chloride medium, and resolved 

 by a Zeiss ^^ homogeneous immersion 

 objective, with an A eye-piece. The 

 markings were clearly and distinctly 

 shown over the whole length of the 

 diatom. 



Thirty-eighth meeting,Tuesday, January 

 26, 1885. The Society took up for con- 

 sideration the discussion, continued from 

 a preceding meeting, of the preservation 

 and mounting of urinary deposits. 



Dr. Caldwell showed crystals which 

 had been mounted in alcohol balsam 

 since last May which showed no signs of 

 change. Dr. Schaeffer said : — For tempo- 

 rary preservation, allow the urine to stand 

 in a conical glass till the sediment has 

 settled, draw of the supernatant fluid and 

 replace it by a mixture of alcohol, 

 glycerin and water in equal parts. Agi- 

 tate the contents of the glass, again draw 

 off the fluid and replace it by more. Con- 

 tinue this process until there can be no 

 trace of urine left. For permanent pres- 

 ervation and mounting he had found this 

 mixture to answer as well as anything for 

 casts, epithelium, etc., though he could 

 not boast of great success. For crystals 

 he advised the use of an aqueous alkaline 

 solution for phosphates, and balsam for 

 other forms. In response to a question 

 by Prof. Seaman, he said that he had never 

 used acetate of alumina to preserve casts. 



Mr. Hitchcock read an extract from a 

 letter from Dr. C. P. Pengra, of Boston, 

 Mass., in which the writer stated that he 

 had numerous mounted specimens of 

 casts, epithelia, etc., and that he had 

 found no medium so satisfactory as the 

 mother liquid itself. Mr. Hitchcock said 

 that this corresponded to his own experi- 

 ence, and that he had had best success 

 with urine to which a little carbolic acid 

 had been added than with any other 

 medium. 



Prof. Seaman showed a slide containing 

 a mixtui'e of several of the more common 

 forms of uric acid, and also slides of uric 

 acid from some of the larger moths. 



Dr. Flint presented for distribution some 

 diatomaceous material dredged by the 

 'Albatross' from a depth 1,440 fathoms. 

 E. A. Balloch, Seer. 



San Francisco, Cal. 



Regular meeting, January 13th. A slide 

 of Biigula {Celhilaria) avicitlaria, one of 

 the marine polyzoa, was donated by Mr. 

 Howard, and shown under polarized light. 



The subject appointed for discussion. 



' Culture Methods used in the study of 

 Micro-organisms,' was introduced by Dr. 

 C. P. Bates. He stated that the absorb- 

 ing interest attending the study of unicel- 

 lular organisms during the past few years, 

 especially of that group known by the 

 generic term bacteria, and the variable 

 conditions under which they require to be 

 observed, had necessitated the use of nu- 

 merous fluid and semi-fluid culture media. 

 A brief description of some of these was 

 given, together with the modes of prepara- 

 tion and preservation usually employed. 

 The respective merits of fluid and of 

 gelatinous media were alluded to. Dr. 

 Bates being evidently inclined to follow 

 Pasteur, in giving preference to the for- 

 mer. By means of apparatus constructed 

 by himself, he demonstrated his method 

 of sterilizing and preserving culture fluids. 

 Various forms of culture tubes were 

 shown, and also numerous other devices. 

 At the conclusion quite an animated dis- 

 cussion arose as to the respective merits 

 of the gelatin method of culture and that 

 of Pasteur, who still employs fluid media 

 in his investigations. 



A. H. Breckenfeld, Seer. 



Exchanges. 



[Exchanges are inserted in this column without 

 charge. They will be strictly limited to mounted ob- 

 jects, and material for mounting] 



Wanted: Cleaned St. Vincent material, for cash. 

 E. A SCHULTZE, 

 Tompkinsville, Staten Island, N. Y. 



For Exchange : Eyes of Limulus, and leaves of 

 Deutzia scabra, rich and beautiful stellate hairs, 

 for finely mounted slides of diatOMi> or polycystina. 

 W. K. DAMON, 



Care of Tiffany & Co., 

 New York City. 



Seeds of Orthocarpus purpurescens in e.vchange 

 for other objects, mounted or unmounted. 



EDWARD GRAY, M. D., 



Benicia, California. 



Diatomaceous clay from this place, and fine slides 

 of Foramnifera, for fine slides, material or back num- 

 bejs of A. M. M. Journal. 



E. H. RICHARDS, 



Woburn, Mass. 



Wanted : Well cleaned and selected Foraminifera, 

 for which cash will be paid or slides given 



EDWARD G. DAY, 



Riverside, Conn. 



Hundreds of varieties of fresh- water Algse, including 

 Volvox, Desmids, Rivularia, Draparnaldia, Tetra- 

 spora, &c., &c., for selected exchanges by list. 



J. M. ADAMS, 

 Watertown, Md. 



